A possible case of pneumoconiosis in a limestone quarry worker.

BACKGROUND: A 43-year-old man presented with wheeze and shortness of breath. He had an occupational history of working in a limestone quarry. Pulmonary function testing revealed a mixed obstructive/restrictive defect. Chest X-ray revealed nodular shadowing throughout both lung fields. METHODS: Subsequent thoracoscopic lung biopsy was performed and histology of the nodules revealed a foreign body granulomatous reaction with numerous fluorescent particles seen under polarized light. There was no evidence of interstitial fibrosis. RESULTS: Energy dispersive X-ray analysis (EDXA) scanning confirmed that these particles contained calcium, aluminium and silicon and had a composition consistent with limestone. CONCLUSIONS: This case demonstrates a possible unusual reaction to inorganic dust particles without resultant fibrosis.

Mediastinal mixed dendritic cell sarcoma with hybrid features.

This report describes a recurrent sarcoma involving the soft tissues of the posterior mediastinum with features of both follicular dendritic and interdigitating dendritic cells. Histologically, the tumour, which was a recurrent neoplasm 19 years after the initial removal, was composed of bland spindle shaped cells with interspersed inflammatory cells, predominantly lymphocytes. Immunohistochemically, the spindle cells were positive for S100 protein, CD45, CD68, and vimentin, but negative for CD21 and CD35 (markers of follicular dendritic cells). The immunophenotype was in keeping with interdigitating dendritic cells. However, ultrastructural examination demonstrated elongated cell processes joined by desmosome-like junctions-features in keeping with follicular dendritic cells. Follicular dendritic cell sarcoma and interdigitating dendritic cell sarcoma are rare neoplasms and a high index of suspicion is required to make a correct diagnosis. Immunohistochemistry and/or electron microscopy are required for a definitive diagnosis. This case shows that hybrid neoplasms can occur, which have features of both follicular and interdigitating dendritic cells.

Epithelioid Hemangioendothelioma of the Spermatic Cord.

This report describes an epithelioid hemangioendothelioma arising on the spermatic cord of a 50-year-old man who presented with a nodule in the right hemiscrotum. Histologic examination showed a cellular tumor composed of epithelioid cells, many of which had intracytoplasmic lumina containing red blood cells. Immunohistochemistry showed focal positivity of tumor cells with the endothelial markers CD34, factor VIII-related antigen, and Ulex and with the anticytokeratin antibodies CAM5.2 and AE1/AE3. Ultrastructural examination revealed polygonal tumor cells forming vascular spaces and intracytoplasmic lumina containing red blood cells. This is the second documented occurrence of epithelioid hemangioendothelioma at this site. The case illustrates the value of immunohistochemistry and electron microscopy in establishing a diagnosis. Int J Surg Pathol 8(1):75-78, 2000