[487] Biclonality in Cutaneous Marginal Zone Lymphoma

Gauri G Panse, Jean M Henneberry. Baystate Medical Center, Springfield, MA

Background: Biclonality is a rare phenomenon in primary cutaneous marginal zone B-cell lymphoma (PCMZL). We reviewed the cases of PCMZL from our files and identified two such cases.
Design: The archives of our pathology files were reviewed from January 2000 to the present for cases of PCMZL, to study their clonal pattern. Thirteen cases were identified, from 8 patients, some with multiple tumors. Five patients had a single tumor biopsied, one patient had 2 concurrent skin excisional biopsies and 2 patients had 3 biopsies each, over a period of 1 month to 2 years. Immunohistochemistry and in-situ hybridization (ISH) studies for kappa and lambda light chains were performed on all the available skin biopsies.
Results: ISH studies revealed the following: 5 cases demonstrated a clonal population of lymphoid cells with kappa-light chain restriction, a lambda-light chain restriction was identified in one case and two cases demonstrated biclonal populations. Of the two cases with biclonality, the first case was a 67 year old female, with a history of two persistent nodules on the back which were approximately 7 cm apart, ranging from 1.0 to 1.5 cm in greatest dimension. ISH studies revealed a kappa-restricted clonal population of lymphoid cells in one lesion, and a lambda-restricted population in the second. These results were repeated to confirm the presence of two separate light chain restricted populations. The second patient was a 79 year old gentleman, with a previously diagnosed PCMZL of the neck and scalp, both tumors showed a kappa-restricted lymphoid population. Three months later he developed a new lesion on the chest which showed a lambda-restricted population of lymphoid cells. All the biopsy specimens showed a dense dermal and subcutaneous lymphocytic infiltrate with admixed plasma cells and occasional germinal centers. The lymphocytes were predominantly small to ovoid with hyperchromatic nuclei and focal monocytoid morphology. Immunohistochemical stains were consistent with PCMZL. Primary cutaneous follicle center lymphoma was excluded by either CD10 or BCL6 stains.
Conclusions: Biclonality has been described in approximately 5% of chronic B-cell proliferative disorders. It is proposed that this represents true biclonality (independent development of distinct clones) or intraclonal evolution (distinct morphological variants arising from a common progenitor clone). This study illustrates the unusual nature of biclonality in PCMZL and the importance of working-up each individual lesion with ISH.
Category: Dermatopathology

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 74, Wednesday Morning


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