Clonal cytogenetic abnormalities in the plasma cell variant of Castleman disease.

Castleman disease (CD) is widely regarded as a non-neoplastic process, yet clonal cytogenetic abnormalities have been rarely reported and are restricted to the hyaline-vascular variant. It remains unclear whether this reflects true rarity in such tumors - the fact that such cases are not routinely submitted for cytogenetic studies, or that suspension culture techniques are erroneously used rather than in situ cultures. We report a localized plasma cell variant of CD (PC-CD) with clonal abnormalities.

KIT(D816V+) systemic mastocytosis associated with KIT(D816V+) acute erythroid leukaemia: first case report with molecular evidence for same progenitor cell derivation.

A case of systemic mastocytosis associated with a clonal haematological non-mast cell lineage disease (SM-AHNMD), where the associated disease is acute erythroid leukaemia (erythroid/myeloid type), is reported. Interestingly, molecular studies showed the KIT(D816V+) mutation not only in the mast cells, but also in the myeloid blast population and the leukaemic erythroid cells. As is the case with most erythroid leukaemias, the patient had a very aggressive clinical course and died shortly after diagnosis.

Automated analysis of fluorescence in situ hybridization on fixed, paraffin-embedded whole tissue sections in B-cell lymphoma.

Certain recurrent cytogenetic abnormalities are diagnostic of a specific neoplasm and may portend prognosis. As conventional cytogenetics may not reveal a neoplastic clone, and unfixed material for fluorescence in situ hybridization may be unavailable, performing fluorescence in situ hybridization on fixed tissues is diagnostically and prognostically valuable. Manual interpretation of fluorescence in situ hybridization signals may be difficult on paraffin-embedded tissue sections due to truncated nuclei.

Nonsecretory variant of immunoproliferative small intestinal disease: a case report with pathologic, immunophenotypic, and molecular findings.

We report a case of the nonsecretory variant of immunoproliferative small intestinal disease involving the distal small bowel and the mesenteric and retroperitoneal lymph nodes in a 19-year-old woman from Mexico. This variant extranodal marginal zone B-cell lymphoma appeared similar in the different sites of involvement, with more interspersed large cells and greater plasmacytic differentiation present in intestinal specimens. Characteristic lymphoepithelial lesions and follicular colonization were seen in intestinal and lymph node sections, respectively.