Difficult Diagnostic and Therapeutic Cases: CASE 2. Thymoma and Tumor Lysis Syndrome in an Adolescent (original) (raw)
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The diversity of pathologic processes that may reside in a small anatomic compartment like mediastinum is impressive. The lesions may be neoplastic and non-neoplastic; and may include proliferation of somatic epithelial, lymphoid, mesenchymal and germ cell types. Anterior mediastinum is the preferred site for mediastinal masses, of which 40% or more are of thymic origin. Again approx. 90% of all thymic masses are in the anterior mediastinum. About 40-50% of patients having anterior mediastinal mass are asymptomatic and when symptoms appear, those are mostly due to structural compression and displacement. These neoplasias are most common in the fifth and sixth decades of life and distributed evenly between men and women. In the present case study autopsy was performed in a case of sudden death, which had history of respiratory distress for some time and was being treated elsewhere by quacks. A huge anterior mediastinal growth was found on autopsy and diagnosis was confirmed by histopathology and immunohistochemistry.
Primary large-cell lymphoma of the thymus
Human Pathology, 1990
Primary mediastinal nonlymphoblastic non-Hodgkin's lymphoma (NLNHL) has distinct clinical, histologic (diffuse largecell morphology, often with sclerosis and clear cytoplasm), and immunohistochemical features (predominantly B-cell lineage, usually immunoglobulin-negative), which suggest origin from a unique B-cell population. The thymus has a resident population of B cells with a unique immunophenotype, and can be involved by primary mediastinal NLNHL, in some cases selectively. Fifteen cases of NLNHL involving the thymus were studied by paraffin-section immunohistochemistry using antibodies to formalin-resistant epitopes of B cells (4KB5 [CD45RA] and L26 [CD20]) and T cells (L60 lCD43] and UCHL1 [CD45RO]). All were diffuse large-cell or immunoblastic lymphomas with sclerosis, and were also similar to primary mediastinal NLNHL in clinical features. Neoplastic cells stained with L26 in all but one case, which stained with 4KB5 and an antibody to a leukocytecommon antigen (PD7/26 [CD45RB]), and were uniformly nonreactive with L60 (with one exception) and UCHL1. Intermingled small lymphocytes were uniformly L26-negative and positive for T-cell markers, even in one case with atypia suggesting a lymphoma of mixed morphology. These findings demonstrate that primary thymic and primary mediasfinal NLNHL are similar B-lineage neoplasms, and support previous sugsesthans that both may originate in thymie B cells.
A rare case of mixed type a thymoma and micronodular thymoma with lymphoid stroma
Journal of pathology and translational medicine, 2015
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A clinicopathologic study of mediastinal lesions with special emphasis on thymomas
International Journal of Research in Medical Sciences, 2015
Background: Mediastinal masses are relatively uncommon lesions that sometimes pose an interesting diagnostic and therapeutic problem for the clinician. Thymomas are one of the common mediastinal neoplasms and exhibit a wide spectrum of morphologic features and an unrivalled frequency of other autoimmune diseases. The great morphologic variability and heterogeneity in thymomas has rendered their histological classification difficult and highly controversial. Methods: This retrospective and descriptive study on thymoma was done in the department of pathology, Kasturba Medical College Mangalore (Manipal University), India over a period of five years from January 2006 to June 2011. Histopathology sections taken were stained with routine Hematoxylin and Eosin stains in every case. Additional stains and immunohistochemistry were done as required. Results: Total number of mediastinal lesions studied was 66, with thymomas making up 15 cases. The age range of patients with thymomas was 22 to 65 years with a mean of 48 years. The most common histologic sub-type of thymoma was B2. Type AB thymoma was associated with bad prognosis. Five cases of thymomas were associated with Myasthenia Gravis. All thymomas showed cytokeratin positivity. Reticulin fibers were seen around individual tumor cells in Type A thymoma while Type B2 showed around tumor nests. Conclusion: Thymomas are rare & interesting neoplasm located in the mediastinum. A histomorphological analysis aided by immunohistochemistry and radiology permits an exact diagnosis and also allows for differentiation between benign and malignant neoplasms.
Clinical Immunology and Immunopathology, 1985
Cell suspensions prepared from 12 specimens of nonneoplastic thymus (6 normal and 6 from patients with myasthenia gravis) and from 17 thymomas were investigated with a panel of monoclonal antibodies. The great preponderance of thymocytes from the I2 nonneoplastic specimens and from 13 of the 17 thymomas (2 of 3 predominantly lymphocytic tumors and 1 I of 12 mixed tumors) displayed the surface phenotype of cortical or common thymocytes. These cells formed rosettes with unsensitized sheep erythrocytes (E-rosettes) at both 4 and 37"C, and reacted with the following monoclonal antibodies: OKTl (thymic and peripheral T cells). OKT6 (common thymocytes), OKTIO (replicating lymphoid cells). OKTI 1 (sheep cell receptor), and both OKT4 (inducerhelper T cells) and OKT8 (cytotoxic-suppressor T cells). Few B cells (lymphocytes with either immunoglobulin or la-like antigen on the cell surface), and few cells with receptors for transferrin and interleukin 2 were detected. Thymocytes from 3 of the 4 remaining thymomas (2 predominantly epithelial tumors and I mixed tumor) displayed surface marker characteristics of medullary thymocytes or peripheral T cells; i.e., they were reactive with OKTI, OKT3 (peripheral T cells). OKTI I. and either OKT4 or OKT8, and were also E-rosette positive only at 4°C and TdT negative. Thymocytes from the final tumor, a lymphocytic thymoma. exhibited an intermediate phenotype. Thus. almost all mixed (I I of 12) and lymphocytic (2 of 3) thymomas were composed predominantly of cortical thymocytes, while the medullary cell was the rule in the two tumors that were predominantly epithelial. c 19x5 ,Acsdemic Pie\\. Inc Monoclonal antibodies have been developed that identify B and T lymphocytes. and distinguish among T-cell subsets (I -3). These reagents have been successfully employed to study T-cell development in the normal human thymus (2, 4-6). However, in human thymoma, the thymocytes, which are frequently much more numerous than the neoplastic epithelial cells . have not been analyzed with such highly discriminating reagents. In this investigation we have utilized a panel of monoclonal antibodies to establish the surface phenotype of thymocyte suspensions prepared from 17 thymomas and I2 samples of nonneoplastic thymus.
A nodular hyperplasia of the thymic epithelium (so-called microscopic thymoma)
Romanian journal of morphology and embryology = Revue roumaine de morphologie et embryologie, 2009
We investigate a case of nodular hyperplasia of the thymic epithelium which was incidentally, microscopically discovered. Macroscopically there was no sign of tumor and the thymus was surgically removed for the therapy of the clinical symptoms of the myasthenia gravis worsened in two years of evolution. Histological in a general appearance of an involuted thymic tissue, a small nodular epithelial proliferation was identified. The epithelial proliferation was classified as A-type in the WHO histological classification of the thymic epithelial tumors. Generally, these microscopic thymomas range from 0.2 mm to 0.4 mm in size that corresponds to our finding that measured 0.25/0.35 mm. This lesion was singular; on additional sections examined, we did not find other areas. Even so, there is a tight connection between the myasthenia gravis, thymomas and these microscopic thymomas, the development of a thymoma from this lesion has not been proven.