Pediatric-Type Follicular Lymphoma in the Dura: A Case Report and Literature Review

Cytomorphologic features of pediatric-type follicular lymphoma on fine needle aspiration biopsy: case series and a review of the literature

INTRODUCTION

Pediatric-type follicular lymphoma (PTFL) is a rare and recently recognized subtype of nodal follicular B-cell lymphoma. While significant recent progress has been made in understanding the morphologic, immunophenotypic, and molecular findings, there are only rare case reports describing the cytomorphologic features of PTFL.

MATERIALS AND METHODS

Four cases of PTFL initially evaluated on fine needle aspiration (FNA) biopsy were retrieved from our institutions' databases. The cytologic and subsequent surgical excision specimens were compared in terms of cytology, histology, immunophenotype, and molecular findings.

RESULTS

A constellation of cytologic features for PTFL are able to distinguish it from other cytomorphologic entities in the differential including: 1) the presence of large blastoid cells with fine chromatin and irregular nuclear membranes, 2) small/intermediate-sized lymphocytes with subtle nuclear membrane irregularities, 3) near complete absence of cytoplasmic vacuoles in lymphoid cells, 4) tingible body macrophages, 5) mitotic figures, 6) absence of a diffuse large cell component, 7) and no significant plasma cell population.

CONCLUSIONS

We present four cases of PTFL initially evaluated on FNA biopsy and define the cytomorphologic features of PTFL. FNA biopsy is presented as a practical tool for initial evaluation of this rare entity as part of a multimodal diagnostic approach, for which increased awareness among cytopathologists can ensure the appropriate triage of specimen studies necessary for the diagnosis. Additionally, we comprehensively review the current literature on PTFL and discuss the differential diagnosis on cytology, including potential pitfalls.

Dural Follicular Lymphoma: Case Report and Literature Review

Follicular lymphoma (FL) usually has an indolent course and presents with painless, waxing and waning lymphadenopathy in the absence of systemic symptoms. It is uncommon for FL to present outside of lymph nodes, although it can develop in the gastrointestinal tract, skin, thyroid, and testes. Central nervous system (CNS) involvement in FL is rare. Most CNS lymphomas are diffuse large B-cell lymphoma, although Burkitt lymphoma, lymphoblastic lymphoma, and peripheral T-cell lymphoma are also observed. These tumors usually involve white matter but may also involve gray matter. Lymphomas of the dura are very uncommon and are usually mucosa-associated lymphoid tissue lymphomas. Here, we present a case of FL of the dura arising in a 62-year-old woman that was responsive to chemotherapy. According to a literature review, there have been 15 previously reported cases of FL of the dura. Dural FL has been most frequently treated with radiation and chemotherapy. Patients were still alive in all cases in which follow-up was reported. Although the sample size is small, these data suggest that dural FL, like other forms of FL, is an indolent disease that is associated with prolonged survival despite usually being incurable.