Diagnosis of monoclonal B cell lymphocytosis (MBL) through transurethral resection of prostate for obstructive lower urinary tract symptoms

Abstract

Incidental diagnosis of haematolymphoid disorders in prostate tissue is rare, with the largest study in the literature reporting a 0.37% incidental lymphoma diagnosis in prostate and associated lymph node tissue. B cell lymphocytosis (MBL) is a relatively recently defined disease entity. The authors present the diagnosis and management of a patient diagnosed with incidental MBL on transurethral resection of prostate (TURP), performed for symptomatic lower urinary tract symptoms refractory to pharmacological therapy. Initially thought to represent chronic lymphocytic leukemia, repeated flow-cytometric analysis confirmed the diagnosis of MBL, and the patient remains under surveillance without the requirement for further medical treatment.

Fig. 1

H&E stain of TURP prostate chips highlighting prostatic tissue infiltrated by small lymphocytic infiltrates, suggestive of a B cell lymphoproliferative disorder. Original magnification ×4.

Fig. 2

2a. Positive staining for CD79a, 2b. Positive staining for CD20, 2c. CD20 positive B lymphocytes expressing CD23, 2d. CD20 positive B lymphocytes expressing CD5.