Nelson Montalvo - Academia.edu (original) (raw)
Papers by Nelson Montalvo
Dermatology Online Journal, Mar 15, 2022
PubMed, Dec 23, 2011
Introduction: Serrated polyps of the large intestine comprise a diverse group of lesions of the c... more Introduction: Serrated polyps of the large intestine comprise a diverse group of lesions of the colonic mucosa that includes hyperplastic polyps, sessile serrated adenomas and traditional serrated adenomas. These lesions have been considered precursors of colorectal carcinogenesis associated with microsatellite instability. Objective: To determine the prevalence of the MLH1 y MSH2 mutations in serrated polyps and to correlate with morphological and cytoarchitectural characteristics. Methods: A descriptive study of 164 serrated colorectal polyps was performed. Tissue microarray technique was used to analyze their morphological and cytoarchitectural features and immunohistochemical expression of the MLH1 and MSH2 mutated genes in different regions of the colonic crypts. Results: One-hundred and fifty-nine hyperplastic polyps, 2 sessile serrated adenomas and 3 traditional serrated adenomas were included. There was no significant difference in the immunohistochemical expression between hyperplastic polyps and serrated adenomas for MLH1 and MSH2. Moreover, the degree of expression decreased from the base toward the surface of the crypt where it was negative. This finding was not a sufficient to qualify for microsatellite instability. Conclusions: The prevalence of the MLH1 and MSH2 mutated genes were similar between hyperplastic polyps and serrated adenomas. No correlation was found with morphological and cytoarchitectural characteristics.
Rare Tumors, Nov 1, 2016
Secretory breast carcinoma is an exceptionally rare mammary gland neoplasia described mainly in a... more Secretory breast carcinoma is an exceptionally rare mammary gland neoplasia described mainly in adult females and children of both sexes, and very rarely in the elderly. It has particular histopathological and immunohistochemical features and a favorable prognosis. We report the case of a 79-year-old Hispanic woman with a palpable breast mass. Currently, the patient is disease free after a follow-up period of 6 years without local recurrence or axillary lymph-nodes nor distant metastases.
Case reports in pathology, Jun 15, 2020
Cutaneous myoepithelioma (CM) is a rare tumor among the primary skin neoplasms. We present the ca... more Cutaneous myoepithelioma (CM) is a rare tumor among the primary skin neoplasms. We present the case of a patient with a diagnosis of CM in the right hypothenar region. Histological study showed a proliferation of myoepithelial cells with a solid, reticular growth pattern in a chondromyxoid stroma. The tumor cells were positive for CK AE, S-100, EMA, and p63.
Journal of Medical Case Reports, Jun 12, 2014
Introduction: Polymelia, or congenital duplication of a limb, is an extremely rare entity in huma... more Introduction: Polymelia, or congenital duplication of a limb, is an extremely rare entity in humans, with few cases reported in the literature. Case presentation: We present the case of a six-month-old Hispanic boy born with a lower limb bud on the left posterior thigh. Conclusion: The infant had a favorable outcome and evolution after surgical treatment of his supernumerary limb, with no after-effects or impairment whatsoever.
Diagnostic Pathology, Jul 3, 2019
Background: Mesonephric adenocarcinoma (MNAC) is a rare tumor of the female genital tract, which ... more Background: Mesonephric adenocarcinoma (MNAC) is a rare tumor of the female genital tract, which originates from mesonephric duct remnants. Its diagnosis is pathologically challenging, because MNAC may exhibit a mixture of morphological patterns that complicates the differential diagnosis. Case presentation: The patient in this case was a 48-year-old woman with a polypoid mass protruding into the endocervical canal. The patient underwent a total hysterectomy outside the institution. During biopsy, the mass showed a cerebroid aspect. Histological study revealed a tumor with a predominantly tubular and ductal growth pattern. The immunoprofile showed negative staining for calretinin, carcinoembryonic antigen (CEAm), estrogen receptors (ER), and progesterone receptors (PR), and positive staining for CD10, p16, and PAX2. The Ki-67 score was 46%. Using a next-generation sequencing assay, we documented genomic alterations in KRAS and CTNNB1, low tumor mutation burden (TMB), and an absence of microsatellite instability. In addition, gain of the long arm of chromosome 1 (1q) was also documented using chomogenic in situ hybridization (CISH). Three years later, the patient presented pulmonary nodules in the lingula and left basal lobe that were resected by thoracotomy. The histopathologic study of the pulmonary nodules confirmed the presence of metastases. Conclusion: Carcinomas of mesonephric origin are among the rarest subtypes of cervical tumors. We report the first case of mesonephric adenocarcinoma of the cervix with lung metastases showing a CTNNB1 gene mutation.
American Journal of Dermatopathology, May 1, 2016
Hydroa vacciniforme-like cutaneous lymphoma is a very rare Epstein-Barr virus positive peripheral... more Hydroa vacciniforme-like cutaneous lymphoma is a very rare Epstein-Barr virus positive peripheral T-cell lymphoma affecting Asian and Hispanic children and young adults with a defective cytotoxic immune response to EBV predisposing to the development of the disease. We report on 2 Ecuadorian patients with papulovesicular and ulcerated crusted lesions on the face, upper and lower extremities and abdomen, with aggressive clinical course and, in one case, a fatal outcome. The histological and molecular profiles (immunohistochemistry and in situ hybridization) established a diagnosis of hydroa vacciniforme-like Epstein-Barr virus-encoded small RNAs + cutaneous T-cell lymphoma in both cases.
International Journal of Gynecological Pathology, 2019
Malignant lipomatous tumors of the vulva are an extremely rare entity. We report the case of a 53... more Malignant lipomatous tumors of the vulva are an extremely rare entity. We report the case of a 53-year-old patient with a nodule on her right labium majus whose histological and immunohistochemical profile (S100 and p16) confirmed a diagnosis of vulvar myxoid liposarcoma.
Case reports in pathology, Mar 17, 2019
Secretory carcinoma (SC) is a recently described entity occurring in the salivary glands. Before ... more Secretory carcinoma (SC) is a recently described entity occurring in the salivary glands. Before its description, SC was frequently classified as acinic cell carcinoma (ACC) or adenocarcinoma, not otherwise specified. Its particular histopathological and immunohistochemical characteristics are reminiscent of breast secretory carcinoma. Moreover, it displays a characteristic t(12;15) (p13;q25) translocation that results in the ETV6-NTRK3 gene fusion. This translocation has not been reported in any other salivary gland carcinoma. Identification of the t(12;15) (p13;q25) translocation is the gold standard for diagnosis, although some cases that do not present this specific translocation have already been reported. In such cases, diagnosis is challenging. In addition, some diagnostic pathology laboratories lack the resources to perform the molecular analysis to diagnose SC. In this scenario, morphology and immunohistochemistry are fundamental. Therefore, we report a case emphasizing the typical morphology of SC and its immunochemical profile to establish a final diagnosis without molecular biology tests. This case aims to demonstrate the importance of recognizing the typical presentation of a rare tumor so that clinicians will be informed or reminded of it and consider this entity among the differential diagnoses, when necessary. Moreover, in low-resource settings where molecular analysis is not available, being familiar enough with the histology of this tumor and using the immunoprofile as a key tool for differential diagnosis would be of great importance in establishing the correct diagnosis. The differential diagnosis includes, above all, acinic cell carcinoma and other salivary neoplasms such as intraductal carcinoma, low-grade mucoepidermoid carcinoma, and adenocarcinoma, not otherwise specified, which is actually a rule-out diagnosis.
Annals of coloproctology, Jan 12, 2023
Granular cell tumors are predominantly benign soft tissue tumors originating from Schwann cells, ... more Granular cell tumors are predominantly benign soft tissue tumors originating from Schwann cells, whereas melanocytic nevi are benign proliferations of melanocytes. We present the case of a patient with the presence of both entities located in the cecum and anal canal, respectively, constituting an extremely rare coincidental finding. A 43-year-old woman was evaluated by colonoscopy for iron-deficiency microcytic anemia that had lasted for 1 year. Colonoscopy demonstrated a macular lesion of 0.3 cm with a melanocytic appearance in the anal canal; at the cecum level, a subepithelial, yellowish, and partially mobile firm nodular lesion measuring 1.3 cm was observed. A histopathological study showed a melanocytic nevus in the anal canal and a granular cell tumor in the cecum. This is the first reported case of a patient with the extremely rare coincidental-incidental finding of these 2 entities at the same time.
Research Square (Research Square), Jan 18, 2021
Background Histiocytic sarcoma (HS) is a very rare monocyte/macrophage-derived hematopoietic syst... more Background Histiocytic sarcoma (HS) is a very rare monocyte/macrophage-derived hematopoietic system tumor with a poor prognosis whose diagnosis is pathologically challenging due to its extreme rarity and histological overlap with various mimicking entities in which histiocytes also predominate. Case Presentation We report the case of a 33-year-old male patient with hemophagocytic lymphohistiocytosis (HLH), purpuric syndrome, and signi cant splenomegaly. The patient underwent splenectomy; subsequent macroscopic examination revealed a spleen weighing 2,065 grams with hyperemic red pulp and multiple infarcts at the periphery. The histological and immunohistochemical study established a diagnosis of primary splenic histiocytic sarcoma (PSHS) with frequent hemophagocytosis. Next-generation sequencing (NGS) demonstrated mutations in FLT3, NOTCH2, and KMT2A, microsatellite stability (MSS), and a tumor mutational burden (TMB) of 2 mut/Mb. The patient's condition deteriorated clinically from the appearance of the rst symptoms and he died six months later from multi-organ failure. Conclusion Primary splenic histiocytic sarcoma (PSHS) is one of the rarest tumors of the hematopoietic system. We report the rst case with mutations in FLT3, NOTCH2, and KMT2A, and associated hemophagocytic lymphohistiocytosis.
Journal of Medical Case Reports, Dec 1, 2013
Introduction: Prostatic blue nevus was first described as a benign lesion of uncertain and contro... more Introduction: Prostatic blue nevus was first described as a benign lesion of uncertain and controversial histogenesis by Nogogosyan in 1963. Currently, 30 cases have been reported in the world literature. Case presentation: A 63-year-old Hispanic man presented with prostatism of several months' evolution. Histopathological examination revealed a blue nevus associated with nodular hyperplasia and acute inflammation. Conclusion: Prostatic blue nevus is a rare and unusual, histologically benign prostatic lesion with limited clinical significance and a favorable prognosis.
Clinical Case Reports, Dec 29, 2016
Sebaceous glands are very rarely found in the esophagus. Existing reports do not contain sufficie... more Sebaceous glands are very rarely found in the esophagus. Existing reports do not contain sufficient epidemiological, etiological, clinical, or prognostic data. Its histogenesis suggests heterotopia or metaplasia. Despite its extreme rarity, correct and generally easy identification enables establishing the proper patient monitoring.
Frontiers in Surgery, Jan 30, 2023
Desmoid fibromatosis is a rare, aggressive borderline lesion arising from soft tissues. Treatment... more Desmoid fibromatosis is a rare, aggressive borderline lesion arising from soft tissues. Treatment will depend on the structures that the tumor has involved. Surgery with negative margins is the recommended strategy as it can usually achieve disease control; however, the tumor's location sometimes does not allow it. Therefore, a combination of medical therapies along with strict surveillance is crucial. We present the case of a 6-month-old boy with a chest mass. After further evaluation, a rapidly growing mediastinal mass involving the sternum and costal cartilage was detected. Desmoid fibromatosis was the final diagnosis.
Journal of Clinical and Experimental Dentistry, 2014
Dermatology Online Journal, Mar 15, 2022
PubMed, Dec 23, 2011
Introduction: Serrated polyps of the large intestine comprise a diverse group of lesions of the c... more Introduction: Serrated polyps of the large intestine comprise a diverse group of lesions of the colonic mucosa that includes hyperplastic polyps, sessile serrated adenomas and traditional serrated adenomas. These lesions have been considered precursors of colorectal carcinogenesis associated with microsatellite instability. Objective: To determine the prevalence of the MLH1 y MSH2 mutations in serrated polyps and to correlate with morphological and cytoarchitectural characteristics. Methods: A descriptive study of 164 serrated colorectal polyps was performed. Tissue microarray technique was used to analyze their morphological and cytoarchitectural features and immunohistochemical expression of the MLH1 and MSH2 mutated genes in different regions of the colonic crypts. Results: One-hundred and fifty-nine hyperplastic polyps, 2 sessile serrated adenomas and 3 traditional serrated adenomas were included. There was no significant difference in the immunohistochemical expression between hyperplastic polyps and serrated adenomas for MLH1 and MSH2. Moreover, the degree of expression decreased from the base toward the surface of the crypt where it was negative. This finding was not a sufficient to qualify for microsatellite instability. Conclusions: The prevalence of the MLH1 and MSH2 mutated genes were similar between hyperplastic polyps and serrated adenomas. No correlation was found with morphological and cytoarchitectural characteristics.
Rare Tumors, Nov 1, 2016
Secretory breast carcinoma is an exceptionally rare mammary gland neoplasia described mainly in a... more Secretory breast carcinoma is an exceptionally rare mammary gland neoplasia described mainly in adult females and children of both sexes, and very rarely in the elderly. It has particular histopathological and immunohistochemical features and a favorable prognosis. We report the case of a 79-year-old Hispanic woman with a palpable breast mass. Currently, the patient is disease free after a follow-up period of 6 years without local recurrence or axillary lymph-nodes nor distant metastases.
Case reports in pathology, Jun 15, 2020
Cutaneous myoepithelioma (CM) is a rare tumor among the primary skin neoplasms. We present the ca... more Cutaneous myoepithelioma (CM) is a rare tumor among the primary skin neoplasms. We present the case of a patient with a diagnosis of CM in the right hypothenar region. Histological study showed a proliferation of myoepithelial cells with a solid, reticular growth pattern in a chondromyxoid stroma. The tumor cells were positive for CK AE, S-100, EMA, and p63.
Journal of Medical Case Reports, Jun 12, 2014
Introduction: Polymelia, or congenital duplication of a limb, is an extremely rare entity in huma... more Introduction: Polymelia, or congenital duplication of a limb, is an extremely rare entity in humans, with few cases reported in the literature. Case presentation: We present the case of a six-month-old Hispanic boy born with a lower limb bud on the left posterior thigh. Conclusion: The infant had a favorable outcome and evolution after surgical treatment of his supernumerary limb, with no after-effects or impairment whatsoever.
Diagnostic Pathology, Jul 3, 2019
Background: Mesonephric adenocarcinoma (MNAC) is a rare tumor of the female genital tract, which ... more Background: Mesonephric adenocarcinoma (MNAC) is a rare tumor of the female genital tract, which originates from mesonephric duct remnants. Its diagnosis is pathologically challenging, because MNAC may exhibit a mixture of morphological patterns that complicates the differential diagnosis. Case presentation: The patient in this case was a 48-year-old woman with a polypoid mass protruding into the endocervical canal. The patient underwent a total hysterectomy outside the institution. During biopsy, the mass showed a cerebroid aspect. Histological study revealed a tumor with a predominantly tubular and ductal growth pattern. The immunoprofile showed negative staining for calretinin, carcinoembryonic antigen (CEAm), estrogen receptors (ER), and progesterone receptors (PR), and positive staining for CD10, p16, and PAX2. The Ki-67 score was 46%. Using a next-generation sequencing assay, we documented genomic alterations in KRAS and CTNNB1, low tumor mutation burden (TMB), and an absence of microsatellite instability. In addition, gain of the long arm of chromosome 1 (1q) was also documented using chomogenic in situ hybridization (CISH). Three years later, the patient presented pulmonary nodules in the lingula and left basal lobe that were resected by thoracotomy. The histopathologic study of the pulmonary nodules confirmed the presence of metastases. Conclusion: Carcinomas of mesonephric origin are among the rarest subtypes of cervical tumors. We report the first case of mesonephric adenocarcinoma of the cervix with lung metastases showing a CTNNB1 gene mutation.
American Journal of Dermatopathology, May 1, 2016
Hydroa vacciniforme-like cutaneous lymphoma is a very rare Epstein-Barr virus positive peripheral... more Hydroa vacciniforme-like cutaneous lymphoma is a very rare Epstein-Barr virus positive peripheral T-cell lymphoma affecting Asian and Hispanic children and young adults with a defective cytotoxic immune response to EBV predisposing to the development of the disease. We report on 2 Ecuadorian patients with papulovesicular and ulcerated crusted lesions on the face, upper and lower extremities and abdomen, with aggressive clinical course and, in one case, a fatal outcome. The histological and molecular profiles (immunohistochemistry and in situ hybridization) established a diagnosis of hydroa vacciniforme-like Epstein-Barr virus-encoded small RNAs + cutaneous T-cell lymphoma in both cases.
International Journal of Gynecological Pathology, 2019
Malignant lipomatous tumors of the vulva are an extremely rare entity. We report the case of a 53... more Malignant lipomatous tumors of the vulva are an extremely rare entity. We report the case of a 53-year-old patient with a nodule on her right labium majus whose histological and immunohistochemical profile (S100 and p16) confirmed a diagnosis of vulvar myxoid liposarcoma.
Case reports in pathology, Mar 17, 2019
Secretory carcinoma (SC) is a recently described entity occurring in the salivary glands. Before ... more Secretory carcinoma (SC) is a recently described entity occurring in the salivary glands. Before its description, SC was frequently classified as acinic cell carcinoma (ACC) or adenocarcinoma, not otherwise specified. Its particular histopathological and immunohistochemical characteristics are reminiscent of breast secretory carcinoma. Moreover, it displays a characteristic t(12;15) (p13;q25) translocation that results in the ETV6-NTRK3 gene fusion. This translocation has not been reported in any other salivary gland carcinoma. Identification of the t(12;15) (p13;q25) translocation is the gold standard for diagnosis, although some cases that do not present this specific translocation have already been reported. In such cases, diagnosis is challenging. In addition, some diagnostic pathology laboratories lack the resources to perform the molecular analysis to diagnose SC. In this scenario, morphology and immunohistochemistry are fundamental. Therefore, we report a case emphasizing the typical morphology of SC and its immunochemical profile to establish a final diagnosis without molecular biology tests. This case aims to demonstrate the importance of recognizing the typical presentation of a rare tumor so that clinicians will be informed or reminded of it and consider this entity among the differential diagnoses, when necessary. Moreover, in low-resource settings where molecular analysis is not available, being familiar enough with the histology of this tumor and using the immunoprofile as a key tool for differential diagnosis would be of great importance in establishing the correct diagnosis. The differential diagnosis includes, above all, acinic cell carcinoma and other salivary neoplasms such as intraductal carcinoma, low-grade mucoepidermoid carcinoma, and adenocarcinoma, not otherwise specified, which is actually a rule-out diagnosis.
Annals of coloproctology, Jan 12, 2023
Granular cell tumors are predominantly benign soft tissue tumors originating from Schwann cells, ... more Granular cell tumors are predominantly benign soft tissue tumors originating from Schwann cells, whereas melanocytic nevi are benign proliferations of melanocytes. We present the case of a patient with the presence of both entities located in the cecum and anal canal, respectively, constituting an extremely rare coincidental finding. A 43-year-old woman was evaluated by colonoscopy for iron-deficiency microcytic anemia that had lasted for 1 year. Colonoscopy demonstrated a macular lesion of 0.3 cm with a melanocytic appearance in the anal canal; at the cecum level, a subepithelial, yellowish, and partially mobile firm nodular lesion measuring 1.3 cm was observed. A histopathological study showed a melanocytic nevus in the anal canal and a granular cell tumor in the cecum. This is the first reported case of a patient with the extremely rare coincidental-incidental finding of these 2 entities at the same time.
Research Square (Research Square), Jan 18, 2021
Background Histiocytic sarcoma (HS) is a very rare monocyte/macrophage-derived hematopoietic syst... more Background Histiocytic sarcoma (HS) is a very rare monocyte/macrophage-derived hematopoietic system tumor with a poor prognosis whose diagnosis is pathologically challenging due to its extreme rarity and histological overlap with various mimicking entities in which histiocytes also predominate. Case Presentation We report the case of a 33-year-old male patient with hemophagocytic lymphohistiocytosis (HLH), purpuric syndrome, and signi cant splenomegaly. The patient underwent splenectomy; subsequent macroscopic examination revealed a spleen weighing 2,065 grams with hyperemic red pulp and multiple infarcts at the periphery. The histological and immunohistochemical study established a diagnosis of primary splenic histiocytic sarcoma (PSHS) with frequent hemophagocytosis. Next-generation sequencing (NGS) demonstrated mutations in FLT3, NOTCH2, and KMT2A, microsatellite stability (MSS), and a tumor mutational burden (TMB) of 2 mut/Mb. The patient's condition deteriorated clinically from the appearance of the rst symptoms and he died six months later from multi-organ failure. Conclusion Primary splenic histiocytic sarcoma (PSHS) is one of the rarest tumors of the hematopoietic system. We report the rst case with mutations in FLT3, NOTCH2, and KMT2A, and associated hemophagocytic lymphohistiocytosis.
Journal of Medical Case Reports, Dec 1, 2013
Introduction: Prostatic blue nevus was first described as a benign lesion of uncertain and contro... more Introduction: Prostatic blue nevus was first described as a benign lesion of uncertain and controversial histogenesis by Nogogosyan in 1963. Currently, 30 cases have been reported in the world literature. Case presentation: A 63-year-old Hispanic man presented with prostatism of several months' evolution. Histopathological examination revealed a blue nevus associated with nodular hyperplasia and acute inflammation. Conclusion: Prostatic blue nevus is a rare and unusual, histologically benign prostatic lesion with limited clinical significance and a favorable prognosis.
Clinical Case Reports, Dec 29, 2016
Sebaceous glands are very rarely found in the esophagus. Existing reports do not contain sufficie... more Sebaceous glands are very rarely found in the esophagus. Existing reports do not contain sufficient epidemiological, etiological, clinical, or prognostic data. Its histogenesis suggests heterotopia or metaplasia. Despite its extreme rarity, correct and generally easy identification enables establishing the proper patient monitoring.
Frontiers in Surgery, Jan 30, 2023
Desmoid fibromatosis is a rare, aggressive borderline lesion arising from soft tissues. Treatment... more Desmoid fibromatosis is a rare, aggressive borderline lesion arising from soft tissues. Treatment will depend on the structures that the tumor has involved. Surgery with negative margins is the recommended strategy as it can usually achieve disease control; however, the tumor's location sometimes does not allow it. Therefore, a combination of medical therapies along with strict surveillance is crucial. We present the case of a 6-month-old boy with a chest mass. After further evaluation, a rapidly growing mediastinal mass involving the sternum and costal cartilage was detected. Desmoid fibromatosis was the final diagnosis.
Journal of Clinical and Experimental Dentistry, 2014