Pediatric-type follicular lymphoma

Pediatric-type follicular lymphoma is a rare subtype of follicular lymphoma that primarily affects children and young adults. It is characterized by its unique clinical, morphological, and genetic features that distinguish it from typical follicular lymphoma seen in adults.

Clinical Features

Pediatric-type follicular lymphoma most commonly presents as localized lymphadenopathy, with the cervical lymph nodes being the most frequently involved site. Unlike adult follicular lymphoma, it is not associated with systemic symptoms such as fever, weight loss, or night sweats. The disease course is typically indolent, with a favorable prognosis.

Morphology

Histologically, pediatric-type follicular lymphoma is characterized by follicular or nodular growth patterns. The neoplastic follicles are composed of a mixture of small cleaved cells (centrocytes) and larger non-cleaved cells (centroblasts). The neoplastic follicles are surrounded by a mantle zone of small lymphocytes, which is a distinguishing feature from adult follicular lymphoma.

Genetics

Genetically, pediatric-type follicular lymphoma is characterized by the absence of the t(14;18)(q32;q21) translocation, which results in the overexpression of the BCL2 gene. This is a key distinguishing feature from adult follicular lymphoma, which is commonly associated with this translocation.

Diagnosis

The diagnosis of pediatric-type follicular lymphoma is based on a combination of clinical, morphological, and genetic features. Immunohistochemical staining is often used to confirm the diagnosis, with the neoplastic cells typically expressing CD20, CD10, and BCL6, but not BCL2 or CD23.

Treatment and Prognosis

The treatment of pediatric-type follicular lymphoma typically involves surgical excision, with or without adjuvant chemotherapy or radiotherapy. The prognosis is generally favorable, with a high rate of long-term survival.