181 A Rare and Aggressive Gamma-Delta (γδ) T-Cell Lymphoma, NOS Presenting as Heart Failure Without Leukocytosis: Clinicopathologic Course and Autopsy Findings

Abstract

A 54-year-old man presenting with acute onset dyspnea on exertion in the absence of leukocytosis was found with global hypokinesis and 20%-25% EF on echocardiogram, consistent with systolic and diastolic heart failure. No evidence of obstructive CAD to support ischemic etiology was noted on catheterization. Microscopy of peripheral blood identified a population of medium to large lymphocytes with high nuclear/cytoplasmic ratios and convoluted, irregular nuclei. Flow cytometry showed a γδ T-cell population brightly expressing CD45 with intermediate forward and side scatter, CD2, CD3, and CD5 expression with loss of CD7, negative CD4 and CD8, upregulated CD57, and negativity of CD10, CD25, CD30, and CD56. A γδ T-cell lymphoproliferative disorder involving peripheral blood was suspected. Three main types include γδ T-cell large granular lymphocyte leukemia (T-LGL), which is indolent, whereas hepatosplenic γδ T-cell lymphoma (HSTCL) and mucocutaneous γδ T-cell lymphoma are aggressive. CD57 expression is specific for γδ T-cell LGL over the aggressive entities, which could suggest an indolent course; however, morphologic characteristics of γδT-cells differ from LGLs and are more suggestive of a lymphoma. Thoracentesis, liver and bone marrow biopsies found a γδ T-cell population identical to those in peripheral blood. A perisinusoidal and periportal pattern of liver involvement argued against HSTCL in which purely intrasinusoidal growth is typical. Expression of D5+, CD7–, CD56–, CD57+, TIA–, granzyme negative, and perforin-negative contrasts with that typical of HSTCL (CD5–, CD7+, CD56+, CD57–, TIA+, granzyme negative, and perforin negative). Also, HSTCL cases usually demonstrate isochromosome 7q, which was not seen in the patient’s lymphoma despite a complex karyotype. Following a rapidly fatal course, autopsy found virtually all body sites except the central nervous system were diffusely involved by γδ T-cell lymphoma of a rare immunophenotype not previously described. Infiltration of cardiac muscle provides a potential underlying etiology for the presenting symptoms of heart failure.