Primary lymphoma of bone: A review

Abstract

Lymphomas commonly occur in lymph nodes, while their origin in extranodal sites is less common. When nodal lymphomas spread systemically, they commonly involve the skeletal system, with bone involvement seen in 16–20% of patients. Lymphoma originating in the bone is rare and designated as primary bone lymphoma (PBL). Oberling was the first person to describe PBL in 1928. Subsequently, in 1932, Parker and Jackson described a series of PBLs under the designation of reticulum cell sarcoma of the bone. The lymphoid origin was later confirmed by the availability of immunohistochemistry. According to the World Health Organization, diagnosing a PBL entails having skeletal tumor(s) without visceral or regional lymph node involvement. PBL accounts for less than 1% of all malignant lymphomas, 7% of malignant bone tumors, and 4–5% of extranodal lymphomas. The majority of the PBLs are primary bone diffuse large B-cell lymphomas (PBDLBCL). Rarely, follicular, marginal zone, anaplastic large cell, Hodgkin, and T-cell lymphomas can originate in bone. In this review, we describe the clinical features, gross and microscopic findings, ancillary studies, differential diagnoses, prognostic markers, and treatment of PBDLBCL. Rare variants of PBL are also described briefly.