Leonard B. Kahn

Chondroid chordoma: Electron-microscopic study of two cases

Chondroid chordoma is an unusual tumor composed of an admixture of chondromatous and chordomatous tissue usually located in the spheno-occipital region. This tumor shares many of the clinical and histologic features of classic chordoma and chondrosarcoma and has been shown to have a better prognosis than either of these lesions. To the best of our knowledge, no ultrastructural studies have been performed in the 26 cases of chondroid chordoma published previously. We document the ultrastructural features of two examples of chondroid chordoma. Certain features such as prominent and dilated rough endoplasmic reticulum, intracytoplasmic glycogen aggregates, and abundant fibrillogranular matrix are common to chordoma, chondrosarcoma, and chondroid chordoma. The presence of well-formed tonofilament desmosome complexes as well as complexes composed of alternating profiles of rough endoplasmic reticulum and mitochondria were seen only in chordoma and chondroid chordoma, but not in cartilaginous tumors. Of particular interest was the finding of crystalline, tubular structures within the rough endoplasmic reticulum of both cases of chondroid chordoma, a finding not described previously. The distinction of chondroid chordoma from classical chordoma is said to be a difficult one at the light-microscopic level, and we suggest that these intraergastoplasmic tubular structures might constitute an extremely helpful differential marker.

Extraskeletal osteosarcoma arising in an ectopic hamartomatous thymus: Report of a case and review of the literature

A unique case of an osteosarcoma arising within a hamartoma of the thymic gland located in the left pleural cavity of an 11‐year‐old girl is described. The presence of abundant mature lamellar bone within this thymic hamartoma provides an explanation for the osseous histogenesis of the sarcoma. The development of an osteosarcoma from extraskeletal osseous tissue is a rare occurrence and has been documented in association with myositis ossificans and most recently in a case of dermatomyositis with metaplastic ossification.

Primary synovial sarcoma of the kidney: a case report with literature review.

We describe a case of primary renal synovial sarcoma (SS) in a 48-year-old man. The patient presented with hematuria and was found to have a large tumor in his left kidney on computed tomography scan. Histology revealed a highly cellular spindle cell neoplasm with minimal pleomorphism. The major differential diagnoses included leiomyosarcoma, hemangiopericytoma, and SS. The presence of focal areas with a biphasic pattern, uniformly positive immunostain for bcl-2, focally positive immunostains for epithelial membrane antigen and cytokeratin, and negative immunostains for CD-34, smooth muscle actin and S-100 established the diagnosis. This was subsequently confirmed by molecular testing for t(X;18) translocation. Since the existence of primary SS in the kidney was first suggested in 1999, to the best of our knowledge a total of 19 cases including the present case have been reported to date. Although primary renal SS is rare, these findings indicate that it should be included in the differential diagnosis of spindle cell tumors of the kidney.

A report of primary brain fibrosarcoma with literature review.

Primary fibrosarcoma of the central nervous system (CNS) is an extremely rare tumor. To the best of our knowledge, only 40 cases have been reported in the literature. We document such a case in a 9-year-old child who presented with a short history of headache and vomiting. A mass was completely removed and histologic examination revealed a primary fibrosarcoma with features resembling solitary fibrous tumor, meningioma, and malignant fibrous histiocytoma. In addition, the tumor was associated with meningioangiomatosis. A primary CNS fibrosarcoma with these features is most unusual and rendered a precise diagnosis difficult.

A report of mesothelial/monocytic incidental cardiac excrescences and a literature review

We report the case of a rare cardiac lesion, mesothelial/monocytic incidental cardiac excrescences, and also provide a review of the literature. Diagnosis of this entity was based on both its unique morphologic features and imunohistochemical stains. Cytokeratin positivity confirmed the epithelial component, mesothelial cells, in the lesion. Positive staining of CD68 in the monocytic-appearing cells revealed the histiocytic nature of the second component of this lesion. Differential diagnoses are discussed. This report emphasizes the diagnostic dilemma encountered with this unusual entity and the possibility of misdiagnosing the epithelial portion as a metastatic lesion or vice versa.

Epstein-Barr Virus-Associated High-Grade B-Cell Lymphoma of Mucosal-Associated Lymphoid Tissue in a 9-Year-Old Boy

We report an unusual case of Epstein-Barr virus (EBV)-associated mucosal-associated lymphoid tissue (MALT) lymphoma involving the lungs, kidneys, and axillary lymph nodes in a child with congenital hypoadrenalism and panhypopituitarism. The patient presented with an aggressive clinical course and histologic evolution. Initial biopsies (1994) of the lung and kidney revealed histologic features of low-grade B-cell MALT lymphoma with lymphoepithelial lesions within the renal tubules and bronchial epithelium. Subsequent biopsies (1996, 1997, and 1999) revealed progressively greater cytologic atypia, polymorphism, and necrosis; an increased mitotic rate; and a preponderance of large cells, indicative of progression from a low-grade to a high-grade MALT lymphoma. Immunophenotyping of the lung and lymph node lesions revealed identical surface marker profiles: cells were CD19(+), CD20(+), immunoglobulin (Ig) G(+), kappa(+), lambda(-), CD5(-), CD10(-), CD23(-), and IgM(-), and also negative for T-cell markers. Genotypic analysis demonstrated the presence of immunoglobulin heavy chain rearrangement and monoclonality of EBV in the lung lesion by Southern blot hybridization and polymerase chain re()action (PCR). The clinicopathologic features suggest that these lesions might represent an immunosupression-related continuum of low-grade to high-grade MALT lymphomas. Infection with EBV may have contributed to this tumors aggressive clinical and histologic evolution.

The application of immunohistochemistry in the diagnosis of bone tumors and tumor-like lesions

Immunohistochemistry (IHC) plays an important role in the diagnosis of some bone tumors, especially in the differential diagnosis of primary from metastatic non-osseous tumors and in the categorization of small-round-blue-cell tumors. This article reviews immunomarkers used in bone tumors and their diagnostic significance.

Immunoproliferative Small Intestinal Disease in an American Patient With Lymphoma and Macroamylasemia

Abstract The current case report describes an American patient who had immunoproliferative small intestinal disease complicated by B-cell lymphoma.

Congenital acute T lymphoblastic leukaemia: report of a case with immunohistochemical and molecular characterisation

A newborn infant with congenital T cell lymphoblastic leukaemia presented with hepatosplenomegaly and pancytopenia at birth and died on the 21st day of multiorgan failure. Biopsy and necropsy examination showed extensive atypical lymphoid infiltrates in the lungs, liver, spleen, kidneys, lymph nodes, and bone marrow. Immunohistochemically, the lymphoid cells were TdT+, CD3+, CD45RO+, and CD10−, CD79a−, CD20−. Genotypic analysis using polymerase chain reaction showed T cell receptor γ chain gene rearrangement and absence of immunoglobulin heavy chain gene rearrangement. This appears to be the first documented case of congenital T cell lymphoblastic leukaemia. The case had unusual histological and immunogenotypic features, disseminated early, and pursued a highly aggressive course. Consideration of the diagnosis is of paramount importance. The immunophenotypic studies and molecular characterisation of such congenital leukaemias are critical in arriving at a definite diagnosis.

Ossifying Fibromyxoid Tumor of the Breast Mimicking Fibroadenoma: A Case Report and Differential Diagnoses

An 80-year-old woman presented with a palpable mass in the right breast. Mammographic findings were consistent with calcified fibroadenoma. An ultrasound was performed that showed a solid nodule with peripheral calcification. A core biopsy was obtained that revealed a spindle cell proliferation with a shell of mature bone. The histologic features, in combination with immunohistochemical studies, were those of an ossifying fibromyxoid tumor. Complete excision of the specimen further confirmed the diagnosis. To the best of our knowledge, this is the first reported case of ossifying fibromyxoid tumor occurring in the breast. We review the current literature on ossifying fibromyxoid tumor and discuss the differential diagnoses when confronted with bland spindle cells on a core biopsy of the breast.