Gregory Moes | Stanford University (original) (raw)

Papers by Gregory Moes

Archives of Pathology & Laboratory Medicine, 2000

Cefotetan disodium–induced hemolytic anemia has been reported previously, and some of these cases... more Cefotetan disodium–induced hemolytic anemia has been reported previously, and some of these cases have been severe or fatal. We describe a case of severe hemolytic anemia that occurred in an 80-year-old woman who received cefotetan prophylactically after surgery for a small bowel obstruction. Eight days after the first dose of cefotetan, the patient developed a severe Coomb test–positive hemolytic anemia. Using flow cytometry, we demonstrated cefotetan-specific antibodies in her posttreatment serum, which were detectable at a serum dilution up to 1:10 000. The patient received corticosteroid therapy and blood transfusions, with improvement of her hematologic parameters, but died 54 days after admission for respiratory failure. To our knowledge, this is the first use of flow cytometry for the detection of cefotetan-induced red blood cell antibodies. This technique offers a sensitive, rapid, objective method for detecting drug-induced antibodies.

Journal of Clinical Oncology, 2013

2062 Background: Meningioma is the most common primary brain tumor in the United States, but ther... more 2062 Background: Meningioma is the most common primary brain tumor in the United States, but there is limited data on clinical outcomes. Methods: We performed descriptive and survival analysis of meningioma cases diagnosed 2001-2010 from the Kaiser Permanente Northern California Cancer Registry, which began inclusion of benign brain tumors in 2001. Datasets provided variables on gender, age at diagnosis, race, and vital status. Chart review extracted additional information on mortality, histology, imaging, tumor size, tumor site, and treatment. We used Kaplan Meier method to calculate overall survival (OS) and disease-free survival (DFS) and log-rank test to compare survival rates by variables. Cox proportional hazard models were used to analyze variables relative to endpoints. Results: 1968 cases in 1792 patients with meningioma were analyzed. 55% of cases had histological confirmation. 5- and 10-year OS and DFS for all groups were 76% & 61% and 89% & 82%. Disease progression and r...

Türk Patoloji Dergisi, 2014

Objective: oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-li... more Objective: oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-like tumors in this age group may belong to other entities. In addition, accurate diagnosis and grading of such lesions using criteria developed for adult oligodendrogliomas prove difficult, and often controversial. Material and Method: during a study of tumors previously diagnosed as pediatric oligodendroglioma, we identified four tumors displayed features of that resembled oligodendroglioma, angiocentric glioma and dysembryoplastic neuroepithelial tumor but could not be classified as either one of these entities. Ther clinical, histological and immunohistochemical features of these cases were investigated in this study. Results: two male (both 9 years old) and two female (ages 4 years and 20 months) patients presented with new onset of seizures. All patients were treated surgically, and two required reoperation. Histologically, the tumors were well-differentiated glial neoplasms with focal angiocentric pattern, delicate vascularity, diffuse growth, infiltrative margins, cortical nodules, focal myxoid areas, and leptomeningeal extension. Immunohistochemical studies showed diffuse nuclear positivity with olig-2 and GFAP antibodies, whereas staining with neuronal markers, eMA, p53, and IdH1 were negative. Fluorescent in-situ hybridization analysis demonstrated intact 1p/19q in all tumors, and there was no ultrastructural evidence of ependymal differentiation. All patients were alive with disease with a mean follow-up of 112 months. Conclusion: These four cases illustrate the morphological diversity of well-differentiated, oligodendroglioma-like glial neoplasms and the uncertainty in their classification among pediatric tumors.

Neurosurgery, 2010

BACKGROUND: Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characte... more BACKGROUND: Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characterized by 2 constant features: a focal “closed” midline defect and a fibroneural stalk that links the skin lesion to the underlying cord. The embryogenesis is hypothesized to be incomplete disjunction between cutaneous and neural ectoderms, thus preventing complete midline skin closure and allowing persistence of a physical link (fibroneural stalk) between the disjunction site and the dorsal neural tube. OBJECTIVE: To illustrate these features in 51 LDM patients. METHODS: All patients were studied with magnetic resonance imaging or computed tomography myelography, operated on, and followed for a mean of 7.4 years. RESULTS: There were 10 cervical, 13 thoracic, 6 thoracolumbar and 22 lumbar lesions. Two main types of skin lesion were saccular (21 patients), consisting of a skin-base cerebrospinal fluid sac topped with a squamous epithelial dome, and nonsaccular (30 patients), with a flat or...

Journal of Neurosurgery: Spine, 2009

Oligodendroglioma of the spinal cord is a rare tumor that most often presents with spinal cord sy... more Oligodendroglioma of the spinal cord is a rare tumor that most often presents with spinal cord symptoms. The authors present a case of spinal cord oligodendroglioma that was associated with cerebral rather than spinal cord symptoms. A 30-year-old woman developed nausea, vomiting, and severe headaches. Magnetic resonance imaging of the brain showed meningeal enhancement. The patient underwent a craniotomy with biopsies of the meninges and brain. The biopsy findings revealed an abnormal arachnoid thickening without tumor cells. The patient later developed hydrocephalus and underwent shunt placement. Cerebrospinal fluid cytological findings were negative for tumor cells or infection. She was found to have a cervical cord lesion at C3–4 that was initially nonenhancing but later enhanced after Gd administration. Biopsy of the cord lesion with partial resection showed a WHO Grade II oligodendroglioma with 1p and 19q deletions determined by fluorescence in situ hybridization. Neurooncologi...

Journal of Neurosurgery, 2005

Object. This is a retrospective review of 146 surgically treated benign and malignant peripheral ... more Object. This is a retrospective review of 146 surgically treated benign and malignant peripheral non—neural sheath tumors (PNNSTs). Tumor classifications with patient numbers, locations of benign PNNSTs, and surgical techniques and adjunctive treatments are presented. The results of a literature review regarding tumor frequencies are presented. Methods. One hundred forty-six patients with 111 benign and 35 malignant PNNSTs were treated between 1969 and 1999 at the Louisiana State University Health Sciences Center (LSUHSC). The benign tumors included 33 ganglion cysts, 16 cases of localized hypertrophic neuropathy, 12 lipomas, 12 tumors of vascular origin, and 11 desmoid tumors. There were four each of lipofibrohamartomas, myositis ossificans, osteochondromas, and ganglioneuromas; two each of meningiomas, cystic hygromas, myoblastoma or granular cell tumors, triton tumors, and lymphangiomas; and one epidermoid cyst. The locations of benign PNNSTs were the following: 33 in the brachia...

Journal of Neurosurgery, 2005

Object. This is a retrospective review of 397 benign and malignant peripheral neural sheath tumor... more Object. This is a retrospective review of 397 benign and malignant peripheral neural sheath tumors (PNSTs) that were surgically treated between 1969 and 1999 at the Louisiana State University Health Sciences Center (LSUHSC). The surgical techniques and adjunctive treatments are presented, the tumors are classified with respect to type and prevalence at each neuroanatomical location, and the management of malignant PNSTs is reviewed. Methods. There were 361 benign PNSTs (91%). One hundred forty-one benign lesions were brachial plexus tumors: 54 schwannomas (38%) and 87 neurofibromas (62%), of which 55 (63%) were solitary neurofibromas and 32 (37%) were neurofibromatosis Type 1 (NF1)—associated neurofibromas. Among the brachial plexus lesions supraclavicular tumors predominated with 37 (69%) of 54 schwannomas; 34 (62%) of 55 solitary neurofibromas; and 19 (59%) of 32 NF1-associated neurofibromas. One hundred ten upper-extremity benign PNSTs consisted of 32 schwannomas (29%) and 78 neu...

Military Medicine

This study evaluated the personality characteristics of senior enlisted and occupationally succes... more This study evaluated the personality characteristics of senior enlisted and occupationally successful Navy submarine personnel. One hundred subjects completed the Schedule for Nonadaptive and Adaptive Personality (SNAP). Results indicated that the traits of detachment, propriety, and workaholism were most descriptive of the sample. Thirty-seven percent met SNAP criteria for a personality disorder, typically antisocial, obsessive-compulsive, or avoidant. The results are discussed in terms of adaptation to environmental demands aboard submarines. Suggestions for further research are offered.

Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery, 2014

The cerebral vasculature and the choroid plexus are innervated by peripheral nerves. The anatomy ... more The cerebral vasculature and the choroid plexus are innervated by peripheral nerves. The anatomy of the vascular supply to the brain and its related perivascular nerves is reviewed. Intracerebral and intraventricular schwannomas most likely come from neoplastic transformation of Schwann cells investing the perivascular nerves and nerves within the choroid plexus.

Turkish Journal of Pathology, 2014

Oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-like tumors i... more Oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-like tumors in this age group may belong to other entities. In addition, accurate diagnosis and grading of such lesions using criteria developed for adult oligodendrogliomas prove difficult, and often controversial. During a study of tumors previously diagnosed as pediatric oligodendroglioma, we identified four tumors displayed features of that resembled oligodendroglioma, angiocentric glioma and dysembryoplastic neuroepithelial tumor but could not be classified as either one of these entities. Ther clinical, histological and immunohistochemical features of these cases were investigated in this study. Two male (both 9 years old) and two female (ages 4 years and 20 months) patients presented with new onset of seizures. All patients were treated surgically, and two required reoperation. Histologically, the tumors were well-differentiated glial neoplasms with focal angiocentric pattern, delicate vascularity, diffuse growth, infiltrative margins, cortical nodules, focal myxoid areas, and leptomeningeal extension. Immunohistochemical studies showed diffuse nuclear positivity with Olig-2 and GFAP antibodies, whereas staining with neuronal markers, EMA, p53, and IDH1 were negative. Fluorescent in-situ hybridization analysis demonstrated intact 1p/19q in all tumors, and there was no ultrastructural evidence of ependymal differentiation. All patients were alive with disease with a mean follow-up of 112 months. These four cases illustrate the morphological diversity of well-differentiated, oligodendroglioma-like glial neoplasms and the uncertainty in their classification among pediatric tumors.

Neurosurgery, 2006

Although radiation injury after stereotactic radiosurgery (SRS), including radiation necrosis (RN... more Although radiation injury after stereotactic radiosurgery (SRS), including radiation necrosis (RN), is often treated with surgical resection, detailed outcome data are lacking after resection of symptomatic radiation-injured regions with imaging characteristics suspicious for RN after SRS for arteriovenous malformations (AVM). We present outcomes in seven such patients. We conducted a retrospective chart review of seven patients with AVMs of Spetzler-Martin Grades II (n = 1), III (n = 2), and IV (n = 4) who underwent helium ion, proton beam, or gamma knife SRS and required resection of RN-suspicious tissue 1 to 24 months after post-SRS symptom onset. Postoperative outcomes included Karnofsky Performance Scale (KPS) score and time to symptomatic improvement. Symptomatic improvement required at least 9 months in the three patients with large regions suspicious for RN (>or=4 cm), whereas of four patients with smaller regions (<4 cm), three showed improvement within 2 months (P < 0.05). The remaining patient, who showed no benefit, underwent resection 2 years after the onset of RN symptoms (compared with <or= 8 mo for the other six patients). Surgery improved KPS scores in four patients with a preoperative KPS score of 50 or lower, but not in three patients with preoperative KPS scores greater than 70 (P < 0.05). Outcomes were not consistently associated with AVM size or location, SRS treatment volume or dose, associated aneurysm, or residual AVM. After SRS for AVMs, resection of symptomatic RN-suspicious tissue areas is beneficial in reversing neurological deficits and improving KPS scores in selected patients. Times to improvement were longer when larger areas were resected. Delaying such surgery after symptom onset may negatively affect improvement.

Acta Neuropathologica, 2008

We present an unusual case of gliosarcoma containing numerous islands of well-diVerentiated melan... more We present an unusual case of gliosarcoma containing numerous islands of well-diVerentiated melanocytes in a 65 year-old man. Melanocytic diVerentiation of medulloblastomas is well described, and it has also rarely been reported in low-grade glial neoplasms. Histologic features and immunophenotyping are helpful in diVerentiating divergent diVerentiation in a gliosarcoma from melanoma. To our knowledge, this is the Wrst description of a gliosarcoma with melanocytic diVerentiation. Awareness of the phenomenon of melanocytic diVerentiation within primary neuroepithelial and glial neoplasms is important to prevent the misdiagnosis of these tumors such as metastatic melanoma or primary melanocytic neoplasms of the CNS.

Archives of Pathology & Laboratory Medicine, 2000

Cefotetan disodium–induced hemolytic anemia has been reported previously, and some of these cases... more Cefotetan disodium–induced hemolytic anemia has been reported previously, and some of these cases have been severe or fatal. We describe a case of severe hemolytic anemia that occurred in an 80-year-old woman who received cefotetan prophylactically after surgery for a small bowel obstruction. Eight days after the first dose of cefotetan, the patient developed a severe Coomb test–positive hemolytic anemia. Using flow cytometry, we demonstrated cefotetan-specific antibodies in her posttreatment serum, which were detectable at a serum dilution up to 1:10 000. The patient received corticosteroid therapy and blood transfusions, with improvement of her hematologic parameters, but died 54 days after admission for respiratory failure. To our knowledge, this is the first use of flow cytometry for the detection of cefotetan-induced red blood cell antibodies. This technique offers a sensitive, rapid, objective method for detecting drug-induced antibodies.

Journal of Clinical Oncology, 2013

2062 Background: Meningioma is the most common primary brain tumor in the United States, but ther... more 2062 Background: Meningioma is the most common primary brain tumor in the United States, but there is limited data on clinical outcomes. Methods: We performed descriptive and survival analysis of meningioma cases diagnosed 2001-2010 from the Kaiser Permanente Northern California Cancer Registry, which began inclusion of benign brain tumors in 2001. Datasets provided variables on gender, age at diagnosis, race, and vital status. Chart review extracted additional information on mortality, histology, imaging, tumor size, tumor site, and treatment. We used Kaplan Meier method to calculate overall survival (OS) and disease-free survival (DFS) and log-rank test to compare survival rates by variables. Cox proportional hazard models were used to analyze variables relative to endpoints. Results: 1968 cases in 1792 patients with meningioma were analyzed. 55% of cases had histological confirmation. 5- and 10-year OS and DFS for all groups were 76% & 61% and 89% & 82%. Disease progression and r...

Türk Patoloji Dergisi, 2014

Objective: oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-li... more Objective: oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-like tumors in this age group may belong to other entities. In addition, accurate diagnosis and grading of such lesions using criteria developed for adult oligodendrogliomas prove difficult, and often controversial. Material and Method: during a study of tumors previously diagnosed as pediatric oligodendroglioma, we identified four tumors displayed features of that resembled oligodendroglioma, angiocentric glioma and dysembryoplastic neuroepithelial tumor but could not be classified as either one of these entities. Ther clinical, histological and immunohistochemical features of these cases were investigated in this study. Results: two male (both 9 years old) and two female (ages 4 years and 20 months) patients presented with new onset of seizures. All patients were treated surgically, and two required reoperation. Histologically, the tumors were well-differentiated glial neoplasms with focal angiocentric pattern, delicate vascularity, diffuse growth, infiltrative margins, cortical nodules, focal myxoid areas, and leptomeningeal extension. Immunohistochemical studies showed diffuse nuclear positivity with olig-2 and GFAP antibodies, whereas staining with neuronal markers, eMA, p53, and IdH1 were negative. Fluorescent in-situ hybridization analysis demonstrated intact 1p/19q in all tumors, and there was no ultrastructural evidence of ependymal differentiation. All patients were alive with disease with a mean follow-up of 112 months. Conclusion: These four cases illustrate the morphological diversity of well-differentiated, oligodendroglioma-like glial neoplasms and the uncertainty in their classification among pediatric tumors.

Neurosurgery, 2010

BACKGROUND: Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characte... more BACKGROUND: Limited dorsal myeloschisis (LDM) is a distinctive form of spinal dysraphism characterized by 2 constant features: a focal “closed” midline defect and a fibroneural stalk that links the skin lesion to the underlying cord. The embryogenesis is hypothesized to be incomplete disjunction between cutaneous and neural ectoderms, thus preventing complete midline skin closure and allowing persistence of a physical link (fibroneural stalk) between the disjunction site and the dorsal neural tube. OBJECTIVE: To illustrate these features in 51 LDM patients. METHODS: All patients were studied with magnetic resonance imaging or computed tomography myelography, operated on, and followed for a mean of 7.4 years. RESULTS: There were 10 cervical, 13 thoracic, 6 thoracolumbar and 22 lumbar lesions. Two main types of skin lesion were saccular (21 patients), consisting of a skin-base cerebrospinal fluid sac topped with a squamous epithelial dome, and nonsaccular (30 patients), with a flat or...

Journal of Neurosurgery: Spine, 2009

Oligodendroglioma of the spinal cord is a rare tumor that most often presents with spinal cord sy... more Oligodendroglioma of the spinal cord is a rare tumor that most often presents with spinal cord symptoms. The authors present a case of spinal cord oligodendroglioma that was associated with cerebral rather than spinal cord symptoms. A 30-year-old woman developed nausea, vomiting, and severe headaches. Magnetic resonance imaging of the brain showed meningeal enhancement. The patient underwent a craniotomy with biopsies of the meninges and brain. The biopsy findings revealed an abnormal arachnoid thickening without tumor cells. The patient later developed hydrocephalus and underwent shunt placement. Cerebrospinal fluid cytological findings were negative for tumor cells or infection. She was found to have a cervical cord lesion at C3–4 that was initially nonenhancing but later enhanced after Gd administration. Biopsy of the cord lesion with partial resection showed a WHO Grade II oligodendroglioma with 1p and 19q deletions determined by fluorescence in situ hybridization. Neurooncologi...

Journal of Neurosurgery, 2005

Object. This is a retrospective review of 146 surgically treated benign and malignant peripheral ... more Object. This is a retrospective review of 146 surgically treated benign and malignant peripheral non—neural sheath tumors (PNNSTs). Tumor classifications with patient numbers, locations of benign PNNSTs, and surgical techniques and adjunctive treatments are presented. The results of a literature review regarding tumor frequencies are presented. Methods. One hundred forty-six patients with 111 benign and 35 malignant PNNSTs were treated between 1969 and 1999 at the Louisiana State University Health Sciences Center (LSUHSC). The benign tumors included 33 ganglion cysts, 16 cases of localized hypertrophic neuropathy, 12 lipomas, 12 tumors of vascular origin, and 11 desmoid tumors. There were four each of lipofibrohamartomas, myositis ossificans, osteochondromas, and ganglioneuromas; two each of meningiomas, cystic hygromas, myoblastoma or granular cell tumors, triton tumors, and lymphangiomas; and one epidermoid cyst. The locations of benign PNNSTs were the following: 33 in the brachia...

Journal of Neurosurgery, 2005

Object. This is a retrospective review of 397 benign and malignant peripheral neural sheath tumor... more Object. This is a retrospective review of 397 benign and malignant peripheral neural sheath tumors (PNSTs) that were surgically treated between 1969 and 1999 at the Louisiana State University Health Sciences Center (LSUHSC). The surgical techniques and adjunctive treatments are presented, the tumors are classified with respect to type and prevalence at each neuroanatomical location, and the management of malignant PNSTs is reviewed. Methods. There were 361 benign PNSTs (91%). One hundred forty-one benign lesions were brachial plexus tumors: 54 schwannomas (38%) and 87 neurofibromas (62%), of which 55 (63%) were solitary neurofibromas and 32 (37%) were neurofibromatosis Type 1 (NF1)—associated neurofibromas. Among the brachial plexus lesions supraclavicular tumors predominated with 37 (69%) of 54 schwannomas; 34 (62%) of 55 solitary neurofibromas; and 19 (59%) of 32 NF1-associated neurofibromas. One hundred ten upper-extremity benign PNSTs consisted of 32 schwannomas (29%) and 78 neu...

Military Medicine

This study evaluated the personality characteristics of senior enlisted and occupationally succes... more This study evaluated the personality characteristics of senior enlisted and occupationally successful Navy submarine personnel. One hundred subjects completed the Schedule for Nonadaptive and Adaptive Personality (SNAP). Results indicated that the traits of detachment, propriety, and workaholism were most descriptive of the sample. Thirty-seven percent met SNAP criteria for a personality disorder, typically antisocial, obsessive-compulsive, or avoidant. The results are discussed in terms of adaptation to environmental demands aboard submarines. Suggestions for further research are offered.

Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery, 2014

The cerebral vasculature and the choroid plexus are innervated by peripheral nerves. The anatomy ... more The cerebral vasculature and the choroid plexus are innervated by peripheral nerves. The anatomy of the vascular supply to the brain and its related perivascular nerves is reviewed. Intracerebral and intraventricular schwannomas most likely come from neoplastic transformation of Schwann cells investing the perivascular nerves and nerves within the choroid plexus.

Turkish Journal of Pathology, 2014

Oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-like tumors i... more Oligodendrogliomas are rare in the pediatric population, and most oligodendroglioma-like tumors in this age group may belong to other entities. In addition, accurate diagnosis and grading of such lesions using criteria developed for adult oligodendrogliomas prove difficult, and often controversial. During a study of tumors previously diagnosed as pediatric oligodendroglioma, we identified four tumors displayed features of that resembled oligodendroglioma, angiocentric glioma and dysembryoplastic neuroepithelial tumor but could not be classified as either one of these entities. Ther clinical, histological and immunohistochemical features of these cases were investigated in this study. Two male (both 9 years old) and two female (ages 4 years and 20 months) patients presented with new onset of seizures. All patients were treated surgically, and two required reoperation. Histologically, the tumors were well-differentiated glial neoplasms with focal angiocentric pattern, delicate vascularity, diffuse growth, infiltrative margins, cortical nodules, focal myxoid areas, and leptomeningeal extension. Immunohistochemical studies showed diffuse nuclear positivity with Olig-2 and GFAP antibodies, whereas staining with neuronal markers, EMA, p53, and IDH1 were negative. Fluorescent in-situ hybridization analysis demonstrated intact 1p/19q in all tumors, and there was no ultrastructural evidence of ependymal differentiation. All patients were alive with disease with a mean follow-up of 112 months. These four cases illustrate the morphological diversity of well-differentiated, oligodendroglioma-like glial neoplasms and the uncertainty in their classification among pediatric tumors.

Neurosurgery, 2006

Although radiation injury after stereotactic radiosurgery (SRS), including radiation necrosis (RN... more Although radiation injury after stereotactic radiosurgery (SRS), including radiation necrosis (RN), is often treated with surgical resection, detailed outcome data are lacking after resection of symptomatic radiation-injured regions with imaging characteristics suspicious for RN after SRS for arteriovenous malformations (AVM). We present outcomes in seven such patients. We conducted a retrospective chart review of seven patients with AVMs of Spetzler-Martin Grades II (n = 1), III (n = 2), and IV (n = 4) who underwent helium ion, proton beam, or gamma knife SRS and required resection of RN-suspicious tissue 1 to 24 months after post-SRS symptom onset. Postoperative outcomes included Karnofsky Performance Scale (KPS) score and time to symptomatic improvement. Symptomatic improvement required at least 9 months in the three patients with large regions suspicious for RN (>or=4 cm), whereas of four patients with smaller regions (<4 cm), three showed improvement within 2 months (P < 0.05). The remaining patient, who showed no benefit, underwent resection 2 years after the onset of RN symptoms (compared with <or= 8 mo for the other six patients). Surgery improved KPS scores in four patients with a preoperative KPS score of 50 or lower, but not in three patients with preoperative KPS scores greater than 70 (P < 0.05). Outcomes were not consistently associated with AVM size or location, SRS treatment volume or dose, associated aneurysm, or residual AVM. After SRS for AVMs, resection of symptomatic RN-suspicious tissue areas is beneficial in reversing neurological deficits and improving KPS scores in selected patients. Times to improvement were longer when larger areas were resected. Delaying such surgery after symptom onset may negatively affect improvement.

Acta Neuropathologica, 2008

We present an unusual case of gliosarcoma containing numerous islands of well-diVerentiated melan... more We present an unusual case of gliosarcoma containing numerous islands of well-diVerentiated melanocytes in a 65 year-old man. Melanocytic diVerentiation of medulloblastomas is well described, and it has also rarely been reported in low-grade glial neoplasms. Histologic features and immunophenotyping are helpful in diVerentiating divergent diVerentiation in a gliosarcoma from melanoma. To our knowledge, this is the Wrst description of a gliosarcoma with melanocytic diVerentiation. Awareness of the phenomenon of melanocytic diVerentiation within primary neuroepithelial and glial neoplasms is important to prevent the misdiagnosis of these tumors such as metastatic melanoma or primary melanocytic neoplasms of the CNS.