Dhruv Kumar

Familial tumoral calcinosis. A clinical, histopathologic, and ultrastructural study with an analysis of its calcifying process and pathogenesis

We describe histopathologic and ultrastructural changes in tumoral calcinosis (TC) occurring in seven siblings from a single family. Tumoral calcinosis appears to be triggered by bleeding followed by aggregation of foamy histiocytes. These in turn are transformed, with participation of collagenolysis, into cystic cavities lined by osteoclast- like giant cells and histiocytes—the lesion resembling adventitious bursae. Movement and friction, forces generated from the periarticular location of the TC lesions, putatively are key to this transformation. Concomitantly, two calcifying events develop, possibly driven by concurrent hyperphosphatemia or endogenous hypervitaminosis D. One occurs on membranous fragments in antiprotease- containing large cytoplasmic vesicles within osteoclast-like giant cells and mononuclear cells lining the TC cavities; the second, in the TC locules on membranous and cellular debris derived from cavity-lining cells and erythrocytes. The TC cavities ultimately fill with calcified material, losing their synovial-like lining, become encapsulated by fibrous tissue, and ossify. Hydroxyapatite may gain entrance to capillary lumens and embolize to the lung. We conclude that TC represents a disordered reparative process that often is exaggerated because episodes of bleeding, caused by TC-induced vascular injury, provoke development of new lesions. The capricious response of TC to treatment is correlated with its morphologic features.

Epstein-Barr virus-associated T-cell lymphoma in a renal transplant patient

Posttransplant lymphoproliferative disorders in organ allograft recipients are most commonly of B cell origin, whereas T cell lymphomas are rarely described. We report a case of T cell immunoblastic large cell lymphoma associated with Epstein-Barr virus (EBV) that occurred in a recipient of a cadaveric renal transplant 7 years posttransplantation. On paraffin immunophenotyping, none of the neoplastic cells stained with the T cell-associated markers used, but did show strong CD30 expression. Flow cytometric studies revealed a predominance of T cells without definite evidence of T cell neoplasia. Frozen section immunophenotyping studies revealed a T cell phenotype with aberrant expression, and genotypic studies demonstrated T cell receptor beta gene rearrangement with germline configuration of immunoglobulin heavy chain and kappa light chain genes, confirming a T lineage. EBV-encoded RNA transcripts were demonstrated within the neoplastic cells by in situ hybridization. Southern blot analysis using probes derived from the terminal repeat region of the virus detected a single restriction band indicating a clonal population. We believe this is the first case of a posttransplant T cell lymphoma in which the EBV genome has been demonstrated. This case also illustrates the pitfalls of paraffin immunophenotyping in the diagnosis of T cell lymphoma.

Lymphoepithelial cyst of the pancreas

Lymphoepithelial cyst of the pancreas is a rare lesion which may mimic a pancreatic pseudocyst or mucinous cystic neoplasm. To our knowledge, this lesion has never been reported in the radiologic literature. We present a patient with lymphoepithelial cyst of the pancreas, and we discuss the radiographic and pathologic findings.

Decay-Accelerating Factor Is Expressed in the Human Endometrium and May Serve as the Attachment Ligand for Dr Pili of Escherichia coli

PROBLEM: We evaluated the hypothesis that different tissue substructures in uteri may express decay accelerating factor (DAF), a complement regulatory protein that also may serve as ligand for bacterial attachment.

AgNOR Area Measurements Differentiate Benign and Malignant Melanocytic Lesions More Accurately than Simple Counting

Comparison of argyrophilic nucleolar organizer region (AgNOR) counts has been found to yield statistically significant differences between benign and malignant conditions albeit with considerable overlap. In this study we compared the size of AgNORs and the nuclear areas, as well as the AgNOR count in 23 benign melanocytic lesions and 9 melanomas. Of these parameters, the ratio AgNOR area/nuclear area was found to be the main discriminating factor between melanoma and all the other benign groups studied, with p values of <0.01 and no overlap. Next to it was the nuclear area, which in our study gave significant differences between the groups evaluated. The total AgNOR area and the largest AgNOR gave results comparable to the simple AgNOR counting in all groups studied, except in Spitz nevus, in which the AgNOR counts were less significant than the other parameters (p = 0.0420). We conclude that the ratio AgNOR area/nuclear area discriminates benign from malignant melanocytic lesions better than AgNOR counts or other parameters studied.

Dendrocyte population in cutaneous and extracutaneous Kaposi's sarcoma

In order to investigate the hypothesis that the spindle cells of Kaposis sarcoma originate from dendrocytes, we stained 22 cases of cutaneous and extracutaneous Kaposis sarcoma for the presence of factor XIIIa. We selected eight lesions from the skin, five from the oral mucosa. four from gastrointestinal mucosa, three from lymph nodes, and one each from esophagus and conjunctiva for this study. The majority of cutaneous and lymph node Kaposis sarcoma lesions had a considerable number of dendrocytes admixed with the spindle tumor cells. Of the five oral mucosal lesions only three showed a focal presence of dendrocytes. No dendrocytes were observed in the lesions biopsied from the gastrointestinal mucosa, esophagus, and conjunctiva. Our findings suggest that the proliferation of dendrocytes seen within the lesions of Kaposis sarcoma in the skin and lymph nodes probably represents a nonspecific host response in organs where they are normally present, and it is unlikely that they constitute the neoplastic cells of Kaposis sarcoma.

Spontaneous mucocele of the upper esophagus: radiologic demonstration.

We present a patient with dysphagia resulting from a pedunculated, spontaneous mucocele of the upper esophagus. We briefly discuss the radiologic, endoscopic and pathologic findings of this unusual lesion.