Discussion:
Malignant lymphomas represent the 3rd most frequent histological subtype of head and neck cancers (12%) after squamous cell carcinoma (46%) and thyroid carcinoma (33%).
Extranodal involvement represents 23% of NHML and 1-4% of HML of head and neck (2).
Four localisations are the most affected: the Waldeyer’s ring, the sinuses and the nasal cavities, the oral cavity and the salivary glands (3).
Waldeyer’s ring, as it is a lymphoid structure, is the site of the most affected by head and neck extra nodal malignant lymphomas (4–8)
1) NHML of the larynx:
Primary laryngeal malignant lymphomas are rare and mainly NHML. They predominantly arise from the supraglottic region (containing follicular lymphoid tissue). A meta-analysis published by Kim et al, reported 57 cases of laryngeal NHML (1). They occur preferentially in elderly men. Clinically they most often manifest as dysphonia, dysphagia, and stridor with or without general signs (9). The diagnosis is confirmed by a biopsy. According to the World Health Organization’s classification for NHMLs, type B is the most common malignant cell phenotype (10, 11).
The initial assessment includes a chest, abdomen and pelvic scan cervico-thoraco-abdominal CT and a cervical Magnetic resonance imaging, a bone marrow biopsy and a serum LDH test. The 18-Fluoro-deoxyglucose positron emission computed tomography (18 FDG TEP) is currently recommended (12). Radiotherapy is the main treatment for indolent early-stage NHML (stage I, II) at a total dose of 24 GY in 12 fractions. It must be combined with a chemotherapy in case of presence of poor prognosis factors. As for aggressive NHML, treatment is based on chemotherapy: R-CHOP regimen (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) followed by consolidating radiotherapy depending on tumor response (13,14). The prognosis is similar to lymph node NHML. Ten years overall survival at is 50 - 60% (11)
2) HML of the larynx:
Primary extra nodal HML remains extremely rare and even exceptional (1-4%) (2) .To our knowledge no case of a laryngeal HML has been reported in the literature. Therefore, this case represents the first one described. The clinical presentation is not specific and very heterogeneous depending on the anatomical localization. The diagnosis is confirmed by an histological and immunoisthochemical analysis (5). The monoclonal antibodies panel used includes CD15 (Leu M1), CD20 (L-26), CD30 (Ber H2), CD45 (LCA), CD45RO (UCHL-1), latent membrane protein type 1 (LMP-1 ; CS1-4) of Epstein-Barr virus (EBV) and polyclonal CD3 and fascin (4,5). The most common subtype is classical mixed cellularity lymphoma (2,4). However, Quinones-Avila et al (5) suggested that the classical nodular-sclerosis and lymphocyte-rich Hodgkin Lymphoma subtypes are more common. This could be explained by the fact that in previous studies lymphomas diagnosis was only based on the histomorphological characteristics and old malignant lymphomas classification systems were used.
Head and neck HML treatment consists in ABVD chemotherapy regimen followed by a radiotherapy at a total dose of 25 to 40 Gy, targeting the Waldeyer ring and the involved cervical lymphnodes fields (8).
This treatment provides excellent disease long-term local control with similar results to those reported in cases of lymph node HML. According to the results of a cohort of 34 patients, head and neck extra nodal HML treated with ABVD or MOPP regimens chemotherapy (mechlorethamine, vincristine, procarbazine, and prednisone) followed by radiotherapy at a total dose of 39.6 Gy, in the MD Anderson Cancer Center at the University of Texas between 1967 and 2007, the 10-year disease-free survival rate was 71% (2).