Solution - Cytology Mystery #4

Aspirate smears contained a monomorphous lymphoid population composed of medium-sized cells with a thin rim of cytoplasm containing multiple small vacuoles. One to two small nucleoli were noted in some cells. Occasional cells with plasmacytoid features were present.
















Cellular degeneration and breakdown were prominent, along with interspersed tingible body histiocytes.

There was no evidence of granulomatous inflammation or of metastatic tumor.




         









Tissue sections from the abdominal wall mass showed a similar lymphoid infiltrate involving the dermis and extending into subcutaneous tissue (see above). A bone marrow biopsy demonstrated focal involvement. Immunostaining was positive for CD20 and CD79a, findings confirmed by flow cytometry with CD10 positivity also observed. Some cells stained for Epstein-Barr virus (EBV) latent membrane protein. In situ hybridization for EBV was positive in numerous cells.

Diagnosis: Non-Hodgkin's lymphoma, consistent with Burkitt's lymphoma.


Post-transplantation lymphoproliferative disorders (PT-LPDs, subclassified by Knowles as plasmacytic hyperplasia, polymorphic lymphoproliferative disorders and malignant lymphoma or multiple myeloma) have been noted as a consequence of various types of solid organ transplantation. Incidence varies according to the type and extent of immunosuppressive therapy. Most cases of lymphoma (approximately 80%) are B-cell neoplasms and are diffuse large B-cell lymphomas (REAL classification); multiple myeloma is another major category. The great majority of B-cell PTLDs are associated with EBV. EBV may also be demonstrated in conjunction with T-cell PTLDs and has been described in NK-like T-cell leukemia following solid organ transplantation. Burkitt's and Burkitt's-like lymphomas are unusual in the post-transplantation setting. PT-LPDs may develop quickly in multiple sites and represent clonally distinct tumors.


References
Knowles, D.M.  Immunodeficiency-associated lymphoproliferative disorders.  Mod Pathol 1999;12(2):200-217.
Natkunam, Y. et al.  Aggressive natural killer-like T-cell malignancy with leukemic presentation following solid organ transplantation.  Am J Clin Pathol 1999;111:663-671.


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