Vincent Cracolici, MD and Raja R. Seethala, MD
The patient is a male in his early 70s with a history of chronic lymphocytic leukemia (CLL) presenting with a PET-avid, 1.8 cm submucosal soft tissue nodule involving the right base of tongue of unknown duration. Associated radiologically suspicious lymph nodes are present in right neck levels IIA and IV.
The nodule was biopsied to reveal a predominantly submucosal proliferation of enlarged, pleomorphic, discohesive, mitotically active cells. Occasional atypical mitoses and multinucleated giant cells are present. Some cells demonstrate extension into the epithelium via Pagetoid spread (Figure 1). There is minimal associated inflammation and no eosinophilia. No overlying dysplasia is present.
Figure 1: Photomicrograph of the base of tongue biopsy demonstrating Pagetoid extension of enlarged, pleomorphic, mitotically active,
discohesive tumor cells (panel A). The tumor cells are predominantly submucosal. There are scattered lymphocytes present
but no significant inflammation and no eosinophilia. Immunohistochemically the tumor cells are strongly positive for
Langerin (panel B) and CD1a (panel C). Tumor cells are moderately positive for S100 (panel D).
In order to further characterize this lesion, immunohistochemical studies were performed. The tumor cells were strongly positive for CD1a, Langerin, and fascin with moderate positivity for S100. Scattered CD68 positive cells were also identified among background cells. CD31 was focally positive. There was no expression of keratin (CK5/6, AE1/AE3, Cam 5.2), ERG, desmin, myogenin, inhibin, calretinin, Factor XIIIa, STAT6, MART1, HMB-45, SOX10, CD21, p40, or p16. Lymphoid markers including PAX5, CD20, CD30, CD3, and CD56 were negative. INI-1 was retained. BRAFVE IHC was negative. EBER in situ hybridization was negative.