Carlos Urmacher

Aggressive natural killer cell lymphoma/leukemia: A recently recognized clinicopathologic entity

We report a comprehensive study of a case of aggressive natural killer cell lymphoma/leukemia, which is characterized by young male predominance, rapidly progressive clinical course, and presence of lymphadenopathy, hepatosplenomegaly, and bone marrow involvement. The leukemic phase is frequently preceded by pancytopenia. The diagnostic clues are the detection of cytoplasmic granules in tumor cells on Wright-Giemsa-stained tissue imprints or smears and a selective loss of T-cell antigens. Immunophenotyping is decisive in making the final diagnosis by showing positive natural killer cell markers (CD16, CD56, and/or CD57), CD2, CD11c, and Ia, but negative CD3, T-cell receptor heterodimers, terminal deoxynucleotidyl transferase, and B-cell markers. Genotyping always shows germline configuration in both immunoglobulin and T-cell receptor genes. The unique feature in this case is its presentation as a testicular lymphoma, which has not been previously reported. Polymerase chain reaction was performed in this case but failed to detect human T-cell leukemia virus type I/II provirus. It is important to recognize this new entity as it is a highly aggressive disease with a rapidly progressive clinical course and fails to respond to any chemotherapeutic regimen available.

Giant myofibroblastoma of the male breast

Myofibroblastoma of the breast is a rare, benign neoplasm, seen predominantly in men. The gross appearance is that of a well-circumscribed nodule, characteristically small, seldom exceeding 3 cm. We report a case of giant myofibroblastoma measuring 10 cm and weighing 169 g in the breast of an 83-year-old man. Light microscopic, immunohistochemistry, and electron microscopic features are described. Histologically, these neoplasms may exhibit a varied cellularity that can be misinterpreted as sarcoma. However, they lack marked cellular pleomorphism, tumor necrosis, and mitosis and are characteristically composed of plump and long bipolar, spindly cells arranged in swirling fascicles with intervening broad collagen bands. As we report, immunostaining is strongly positive for vimentin, desmin, and muscle common antigen and negative for cytokeratins and S-100-associated protein. Electron microscopy shows predominantly cells suggestive of myofibroblastic differentiation. The patient has remained free of disease 2 years after mastectomy.

Mycobacterium avium subspecies paratuberculosis and Crohn's disease granulomas.

Objective. Chronic infection with Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) has been proposed as a cause of Crohns disease. Although numerous investigators have examined the link between M. paratuberculosis and Crohns disease, the evidence remains controversial. The aim of this study was to examine intestinal granuloma from Crohns patients for M. paratuberculosis using a semi-nested M. paratuberculosis-specific IS900 polymerase chain reaction (PCR). Material and methods. Paraffin-embedded ileal or colonic tissues of patients with Crohns disease were analyzed. Microdissection of this tissue into “granulomas” and “not granulomas” was performed. On the basis of sequences reported in GenBank alignments, we designed primer sets specific for M. paratuberculosis. The presence of the M. paratuberculosis was examined by semi-nested IS900-specific PCR with human β-actin gene as a control for DNA quality. Results. Biopsies from 20 Crohns patients were examined. Human β-actin gene was amplified in all samples. M. paratuberculosis DNA was detected in the microdissected granuloma in 1 (5%) patient with Crohns disease and in none of the “not granuloma” tissues. Conclusions. M. paratuberculosis DNA can rarely be detected within Crohns granuloma. These results do not support M. paratuberculosis as the primary etiology of Crohns disease.

Kaposi's sarcoma and cytomegaloviral ileocolitis complicating long-standing Crohn's disease in an HIV-negative patient

A 67-yr-old woman with a 25-yr history of Crohns disease, maintained on near-continuous corticosteroids (prednisone 10 mg daily) over a 6-yr period, underwent ileocolic resection for obstruction. Pathology revealed Crohns disease, multiple nodules of Kaposis sarcoma, and cytomegalic inclusion bodies with confirmation of cytomegalovirus by shell vial immunofluorescence. Testing for HIV serum antibody has been repeatedly negative. Crohns disease, Kaposis sarcoma, and cytomegalovirus have been clinically in remission for 5 yr.