Nodal marginal zone lymphoma associated with extensive epithelioid histiocytes.

Nodal marginal zone lymphoma (NMZL) is a rare type of non-Hodgkin lymphoma. In this report, we describe a similar condition affecting female 53-year-old presented with generalized lymphadenopathy and high LDH level. The patient underwent excision of cervical lymph node and bone marrow biopsy. Histopathological examination of the excised lymph node revealed florid infiltrate by epithelioid histiocytes, which greatly underscores the neoplastic process directing the diagnosis towards reactive lesions such as toxoplasmosis, marginal zone hyperplasia or monocytoid B-cell hyperplasia. Careful histopathological examination of interfollicular and parafollicular regions helped in recognition of the pale monomorphic neoplastic cells that showed immunoreactivity for CD20 and Bcl-2 and lacked expression for CD5, CD10 and CD23. The involvement of bone marrow by the same type of cells has excluded the possibility for reactive conditions. The recognition of NMZL is sometimes difficult when benign components predominate such as the presence follicular hyperplasia and epithelioid cell clusters. However, full clinical data including LDH level and asking for bone marrow biopsy were greatly helpful in identifying the correct lesion.