Mass-forming extramedullary hematopoiesis diagnosed by fine-needle aspiration cytology.

Extramedullary hematopoiesis (EMH) is usually a microscopic finding. However, it may present as a mass-forming lesion making it amenable to fine-needle aspiration biopsy (FNAB). When mass-forming EMH occurs, it can simulate a neoplasm clinically and radiologically. Additionally, the megakaryocytes can mimic malignant neoplastic cells, particularly if EMH is not a considered diagnosis. We report six cases of mass-forming EMH diagnosed by FNAB and evaluate the utility of FNAB in diagnosing EMH. Four patients had prior diagnoses of hematologic disorders, one patient had malignant mastocytosis who presented with lymphadenopathy and one patient had a history of carcinoma. The patients' ages ranged from 46 to 78 yr with an equal sex distribution. Aspirate smears showed trilineage hematopoiesis. The cytomorphologic differential diagnosis included metastatic carcinoma, Hodgkin lymphoma and myeloid sarcoma. No special stains were necessary due to the classic cytologic findings and prior hematologic history.

Subcutaneous panniculitic T-cell lymphoma in a cardiac allograft recipient.

BACKGROUND: Post-transplant lymphoproliferative disorder (PTLD) is the third leading cause of death in heart transplant patients beyond the immediate peri-operative period (Ouseph R, Denny DM, Erbeck KM. J Am Soc Echocardiogr 1998; 11: 758; Armitage JM, Kormos RL, Stuart RS, et al. J Heart Lung Transplant 1991; 10: 877; Swinnen LJ, Mullen M, Carr TJ, et al. Blood 1995; 86: 3333; Ying AJ, Myerowitz D, Marsh WL. Ann Thorac Surg 1997; 64: 1822). The majority of PTLD cases are of B-cell origin whereas T-cell neoplasms have been reported as rare, aggressive, and late complications of solid-organ transplantation (Fatio R, Sutsch G, Mayer K, et al. Transplant Proc 1998; 30: 1118). CASE REPORT: A 50-year-old cardiac allograft heart transplant patient presented with subcutaneous nodules involving his trunk and extremities. RESULTS: Light microscopy revealed features characteristic of subcutaneous panniculitic-like T-cell lymphoma. Immunohistochemical analysis showed expression for CD45RO, TIA-1, and focal CD3 positivity by tumor cells. Flow cytometry performed on a subsequent subcutaneous nodule demonstrated an abnormal T-cell population with expression of CD3, CD8, CD56, and T-cell receptor alpha-beta, and no expression of CD4. T-cell gene rearrangement studies revealed a clonal population of cells with a bi-allelic gene rearrangement. CONCLUSION: We report a case of an unusual subtype of PTLD in a cardiac allograft recipient.