S-100 Negative Granular Cell Tumor (So-called Primitive Polypoid Non-neural Granular Cell Tumor) of the Oral Cavity

Abstract

Four cases of cutaneous S-100 negative granular cell tumor were described in 1991. Until now, only 3 cases of oral involvement have been documented in English literature. Two additional cases of oral S-100 negative granular cell tumor are described. Immunohistochemical markers were applied to exclude other lesions that may show the presence of granular cells. The clinical findings were correlated with the histopathological and immunohistochemical features to arrive at the appropriate diagnosis. S-100 negative granular cell tumors are erythematous polypoid masses commonly mistaken for granulation tissue or a pyogenic granuloma. Any part of the oral cavity may be affected. Histopathologically, the lesions consist of sheets, nests, and fascicles of granular cells that are S-100 negative. The granular cells are non-reactive to SMA, HMB45, Melan A, and CD163. The intracytoplasmic granules are diffusely and strongly positive to NKI/C3. The cell lineage of the S-100 negative granular cell tumor is obscure. Absence of staining with CD163 excludes a histiocytic lineage. Absence of staining with S-100 excludes a neural origin. Absence of staining with S-100 and key melanoma markers HMB45 and Melan A also excludes a melanocytic origin. In this context, positive reactivity with NKI/C3 is indicative of presence of intracytoplasmic lysosomal granules only. Greater awareness of this lesion in the oral cavity will result in better characterization of its biologic potential.

Similarity between non‐neural granular cell tumors and granular cell fibrous papules

“…Regrettably, in the study, the authors did not consider the pre-existing literature cases of the glabrous mucosal lesions; particularly, 5 NNGCT cases of the oral cavity have been previously reported. [2][3][4][5] Although the fact that NNGCTs can arise in the glabrous mucosa can reject the conclusion by Fernandez-Flores et al, in my review of the literature, some of these oral cases might have been incorrectly diagnosed. At least 1 of the 5 oral cases could be a histiocytic lesion, as histiocytoid cytomorphology was observed and immunohistochemical analysis was insufficient.…”

Three additional cases of non‐neural granular cell tumor with novel immunohistochemical findings

“…3 However, other locations have been reported, the oral cavity being the most common extracutaneous site. 4 T A B L E 2 Immunohistochemical studies performed Epithelioid cell histiocytoma (ECH) may also show granular cell changes, and its resemblance to the exophytic variant of NNGCT has been reported previously. 12,13 It has been suggested that ECH with granular cell change and NNGCT are one and the same neoplasm, 14 particularly in light of a recent description of ALK overexpression in both tumors.…”

“…NNGCT usually presents as a polypoid or plaque‐like lesion, most commonly on the trunk 3 . However, other locations have been reported, the oral cavity being the most common extracutaneous site 4 …”

Oral granular cell tumour: A multicentric study of 56 cases and a systematic review

“…During the selection process of the systematic review, five publications reporting 6 S100 (−) cases were excluded (Basile & Woo, ; Lerman & Freedman, ; Mejía, Rubiano, Osorio, & González, ; Rawal & Dodson, ; Solomon & Velez, ). These lesions occurred more commonly in men, and the clinical image was different to normal oral GCT, with one lesion developing in the alveolar ridge over a tooth extraction site (Lerman & Freedman, ).…”