Vallecular Large B-Cell Lymphoma: An Uncommon Presentation of Follicular-Origin Disease

The vallecula is a mucosal recess of the hypopharynx situated between the base of the tongue and the lingual surface of the epiglottis and bordered laterally by the glossoepiglottic folds. Lesions in this region are uncommon and encompass a broad differential diagnosis, including vallecular cysts, lingual tonsil hypertrophy, minor salivary gland tumors, squamous cell carcinoma, and, rarely, lymphoproliferative disease. Primary extranodal non-Hodgkin lymphoma of the vallecula is exceptionally rare, and follicular large B-cell lymphoma (FLBCL) has not previously been reported at this site. We present the case of a 62-year-old man who presented with progressive dysphagia and persistent globus sensation for 2-3 months. Flexible laryngoscopy demonstrated a well-circumscribed, smooth, cystic-appearing, pedunculated vallecular mass without mucosal ulceration or airway compromise. The patient underwent direct microlaryngoscopy with transoral excisional biopsy. Histopathologic evaluation revealed a high-grade lymphoid neoplasm. Immunophenotyping demonstrated positivity for cluster of differentiation 20 (CD20), cluster of differentiation 10 (CD10), and B-cell lymphoma 6 (BCL6), with co-expression of B-cell lymphoma 2 (BCL2), an elevated Ki-67 proliferation index, and light-chain restriction. Fluorescence in situ hybridization excluded common rearrangements, supporting a diagnosis of CD10-positive LBCL of follicular germinal center origin, classified as FLBCL according to the World Health Organization 5th edition classification of tumors. The patient was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), followed by involved-site radiotherapy (30 Gy), and achieved a complete metabolic response on surveillance positron emission tomography at six months. The literature on lymphoma involving the vallecula and tongue base is limited to small series and isolated case reports. Diffuse LBCL (DLBCL) predominates, whereas other histologic subtypes have been reported only sporadically. Presentations are typically characterized by dysphagia and globus sensation, and definitive diagnosis requires adequate tissue sampling. To our knowledge, this case represents the first reported occurrence of FLBCL arising in the vallecula. Lymphoma should be considered in the differential diagnosis of atypical or persistent vallecular masses, and adequate submucosal tissue sampling is essential for establishing the diagnosis, particularly in lesions with benign-appearing features.