Abstract
BackgroundSpindle cell squamous cell carcinoma is an uncommon variant of squamous cell carcinoma; its diagnosis is sometimes challenging because it histopathologically resembles neoplastic or reactive spindle cell lesions of mesenchymal origins. Here, we report a rare case of spindle cell squamous cell carcinoma exhibiting prominent neutrophil phagocytosis.Case presentationA 69-year-old Japanese man presented with pain and a polypoid mass on the lower left gingiva. He had received chemoradiotherapy for squamous cell carcinoma of the buccal mucosa 15 years prior to this consultation. In addition, he was treated for mandibular osteonecrosis 6 years after chemoradiotherapy without evidence of cancer recurrence. A biopsy revealed atypical spindle or pleomorphic cells scattered in the edematous and fibrin-rich stroma; however, no malignant squamous components were apparent. These atypical cells frequently contained neutrophils within their cytoplasm that formed cell-in-cell figures. Immunohistochemically, the atypical cells were negative for cytokeratins, epithelial membrane antigen, and E-cadherin, but positive for p63, vimentin, and p53. Although these findings suggested spindle cell squamous cell carcinoma, it was difficult to reach a definitive diagnosis. Based on a clinical diagnosis of a malignant tumor, the patient underwent a hemimandibulectomy. The surgically resected specimen had a typical spindle cell squamous cell carcinoma histology consisting of biphasic spindle cells and conventional squamous cell carcinoma components. Moreover, the surgical specimen also exhibited spindle tumor cells that frequently included neutrophils, around which intense staining for lysosomal-associated membrane protein 1 and cathepsin B was observed. This suggested that the cell-in-cell figures represent active neutrophil phagocytosis by tumor cells, and not emperipolesis.ConclusionThe presence of neutrophil phagocytosis may be a potent indicator of malignancy.
Highlights
The presence of neutrophil phagocytosis may be a potent indicator of malignancy
Spindle cell squamous cell carcinoma (SCSCC) is an uncommon variant of squamous cell carcinoma (SCC) that is characterized by spindle and/or pleomorphic cells [1]
We previously demonstrated that the phagocytosis of apoptotic oral SCC cells by neighboring SCC cells is mediated by activation of Rasrelated C3 botulinum toxin substrate 1 (Rac1) and promotes cell migration [12]
Summary
Spindle cell squamous cell carcinoma (SCSCC) is an uncommon variant of squamous cell carcinoma (SCC) that is characterized by spindle and/or pleomorphic cells [1]. These findings were highly suggestive of a malignancy, and SCSCC and post-irradiation sarcoma were considered in the differential diagnosis, given that the patient had a history of chemoradiotherapy for treating SCC of the buccal mucosa 15 years before. Because the atypical spindle cells were concomitant with the conventional SCC component, we diagnosed the lesion as SCSCC.
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