Recent Advances in Follicular Lymphoma: Pediatric, Extranodal, and Follicular Lymphoma in Situ

Bridging clinicopathologic features and genetics in follicular lymphoma: Towards enhanced diagnostic accuracy and subtype differentiation

Follicular lymphoma (FL) is a neoplasm that originates from germinal center B cells and typically forms at least a partial follicular pattern. Approximately 85% of FL cases harbor the t(14;18)(q32;q21)/IGH::BCL2 which leads to the overexpression of BCL2. These cases are referred to as classic FL in the current World Health Organization classification [1]. These neoplasms often exhibit hallmark epigenetic deregulation due to recurrent mutations in genes such as KMT2D, CREBBP, and EZH2, with KMT2D and CREBBP considered founding events in FL lymphomagenesis. In contrast, about 15% of FL cases are negative for the t(14;18), which could present diagnostic challenges. These cases may lack the typical genetic markers and require careful pathological and molecular analysis for accurate diagnosis. This review aims to provide an up-to-date pathology resource on FL, focusing on the pathological and molecular characteristics of these neoplasms. We will detail the diagnostic criteria for FL and emphasize the importance of genetic and mutational analyses in accurately characterizing and distinguishing FL subtypes. Furthermore, we will propose methodologies and best practices for the diagnostic work-up of FL to enhance diagnostic accuracy.

Oral follicular lymphoma: a clinicopathologic and molecular study

Follicular lymphoma is a hematolymphoid neoplasm that originates from germinal center B cells. It is made up of a combination of small cleaved centrocytes and a varying quantity of larger non-cleaved centroblasts to describe the clinical, microscopic, immunohistochemical, and molecular features of oral follicular lymphomas. Follicular lymphomas affecting the oral cavity were retrieved from pathology files. Immunohistochemistry was performed to confirm the diagnosis, and fluorescence in situ hybridization (FISH) was employed to detect rearrangements in BCL2, BCL6, and MYC genes. Clinical and follow-up data were obtained from the patient's medical and pathology files. Twenty cases were obtained. There was an equal sex distribution (10 males: 10 females) and a mean age of 60.9 years (range: 10-83 years-old). Lesions presented as asymptomatic swellings, usually in the palate (10 cases) and the buccal mucosa (7 cases). Five patients presented with concomitant nodal involvement. Microscopic evaluation depicted the follicular growth pattern with diffuse areas in six cases. Grades 1 and 2 follicular lymphomas represented 12 cases, while grade 3A neoplasms accounted for other 8 cases. Two cases showed rearrangements in MYC, BCL2, and BCL6 genes, while single BCL2 translocation was found in eight cases. Two cases had no translocation. Three patients deceased and the 2-year overall survival achieved 88%. Follicular lymphoma affecting the oral cavity is uncommon, usually affects the palate as a non-ulcerated swelling and the presence of a systemic disease most always be ruled out.

An unusual case of pediatric-type follicular lymphoma: A case report

RATIONALE

Pediatric-type follicular lymphoma (PTFL) is a rare neoplasm with features that differ from those of adult-type follicular lymphoma. Compared to patients with adult-type follicular lymphoma, PTFL patients often show an excellent response. Preoperative diagnosis is challenging and, therefore, an accurate diagnosis is based on the findings of postoperative pathological examination and immunohistochemistry.

PATIENT CONCERNS

A 13-year-old boy presented with a slow-growing mass on the right side of his neck.

DIAGNOSES

The patient was diagnosed with PTFL based on the findings of histopathological examination and immunohistochemistry.

INTERVENTION

The mass was completely resected.

OUTCOMES

After 12 months of postoperative follow-up, the patient achieved good recovery without recurrence.

LESSONS

The optimal treatment for PTFL has not yet been defined. However, patients with PTFL always show satisfactory prognoses, regardless of treatment strategy (targeted radiotherapy, multiagent chemotherapy, or "watch and wait" strategy). Clinically, pathological and immunohistochemical analyses are necessary in the diagnoses of PTFL cases, especially for distinguishing PTFL from reactive follicular hyperplasia, to avoid unnecessary treatment.

Pediatric Tonsil Cancer: A National and Institutional Perspective

OBJECTIVE

To evaluate childhood and adolescent tonsil cancer incidence and to identify the clinical characteristics indicative of those patients who would benefit from urgent operative intervention.

STUDY DESIGN

The Surveillance, Epidemiology and End Results 18 database, inclusive of national cancer statistics from 1973 to 2013, provided quantitative tonsil cancer incidence data. An institutional retrospective chart review of pediatric patients diagnosed with tonsil malignancy from January 2013 to January 2017 identified supplementary qualitative clinical presentation information.

RESULTS

The Surveillance, Epidemiology and End Results 18 database included 138 pediatric patients with tonsil cancer with an age-adjusted incidence rate of 0.021/100 000 patients per year. The majority of cases were unilateral (79.7%), and there was both a male and Caucasian predominance. Non-Hodgkin lymphoma (84.1%) was the most common malignancy, of which Burkitt lymphoma (31.1%), diffuse large B-cell lymphoma (26.8%), and follicular lymphoma (10.1%) were the most common subtypes. Five tonsillar malignancy patients were identified upon institutional chart review. The majority likewise had non-Hodgkin lymphoma and all shared a history of rapid tonsillar enlargement over ≤12 weeks. Significant tonsillar asymmetry was present in 4 patients. Four patients additionally exhibited prominent cervical lymphadenopathy.

CONCLUSIONS

Pediatric tonsil cancer is rare, with non-Hodgkin lymphoma accounting for the majority of pediatric tonsillar malignancies. A high index of suspicion is appropriate in children who present with relatively rapid tonsil enlargement, tonsillar asymmetry characterized by a difference in tonsillar size of ≥2 degrees on the Brodsky scale, or concurrent prominent cervical lymphadenopathy.