Primary squamous cell carcinoma of the salivary gland: immunohistochemical analysis and comparison with metastatic squamous cell carcinoma

Abstract

Background Primary squamous cell carcinoma (SCC) of the salivary gland is a rare disease, and distinguishing primary SCC from metastatic SCC is difficult. This study investigated the histological and immunohistochemical differences between primary and metastatic salivary gland SCC to improve the accuracy of diagnosis and to explore the pathogenesis of this disease. Methods Data of 16 patients who underwent surgery for SCC of salivary glands between 2000 and 2018 at Asan Medical Center were retrieved. Eight patients had a history of SCC at other sites, and eight patients had only salivary gland SCC. Immunostaining for p16, p53, androgen receptor (AR), gross cystic disease fluid protein 15 (GCDFP-15), and c-erbB2, as well as mucicarmine staining, were compared between the two groups. Results Most tumors were located in the center of the salivary glands with extraparenchymal extension. The histology of primary SCC of the salivary gland was consistent with moderately differentiated SCC with extensive desmoplastic reaction and peritumoral inflammation. Involvement of the salivary gland ducts and transition into the ductal epithelium were observed in two cases. Metastatic SCC resembled the primary tumor histologically and was associated with central necrosis. Both groups exhibited negative mucin staining. Two, one, and one primary SCC case exhibited AR, GCDFP-15, and c-erbB2 positivity, respectively. Conclusions A subset of primary SCCs originated in salivary ducts or was related to salivary duct carcinoma. Distinguishing primary from metastatic SCC of the salivary gland is difficult using histologic features and immunoprofiles. A comprehensive review of the medical history is essential.

Pembrolizumab as a first line therapy in a patient with extensive mucoepidermoid salivary gland carcinoma. A complete clinical, radiological and pathological response. A very specific case

“…SCC and high grade MEC have similar histopathologic features and presence of intermediate and mucus cells are the only key for differentiation [ 22 , 23 ].…”

Parotid Salivary Duct Carcinoma With a Prominent Squamous Component: Immunohistochemical Profile, Diagnostic Pitfalls, and Therapeutic Implications

“…6,7,9 Primary or secondary/metastatic SCC is usually a diagnosis of exclusion, which is usually ruled out by the presence of the classical, "breast carcinoma-like" infiltrating, glandular pattern of SDC. 10,11 In the current case, however, relying solely on morphology presented a potential diagnostic pitfall, since there was no SDC component seen in either the initial primary site biopsy or contralateral neck lymph node or skin metastases. Ancillary IHC studies can be particularly helpful in these instances, since the majority of SDC show strong AR nuclear expression (85%) and cytoplasmic gross cystic disease fluid protein 15 (GCDFP-15) (66%-80%), and low molecular weight cytokeratins like CAM5.2 (46%).…”

“…Ancillary IHC studies can be particularly helpful in these instances, since the majority of SDC show strong AR nuclear expression (85%) and cytoplasmic gross cystic disease fluid protein 15 (GCDFP-15) (66%-80%), and low molecular weight cytokeratins like CAM5.2 (46%). 1,3,6,7,9,10 Although primary SCC of the parotid can show AR positivity in 25% of cases, 2 primary cases of SCC of the parotid are exceedingly rare and therefore the more likely distinction will be between an AR-negative skin SCC metastasis to the parotid and an AR-positive primary SDC. High molecular weight cytokeratins like CK5/6 and CK903 can be helpful when evaluating for an in situ component of SDC, which shows reactivity in its basal layer analogous to its utility in evaluating ductal carcinoma in-situ (DCIS) of the breast.…”

Cancer Stem Cell Markers in Squamous Cell Carcinomas of the Salivary Glands

“…To this day, differentiation between primary SCC of the salivary glands and metastatic disease cannot securely be achieved by histology or immunohistochemistry [10]. Whole genome sequencing with mutational analysis may be beneficial in making this distinction [11].…”

“…However, this approach is technically very demanding. Most studies that address this issue [10,12] commonly take a clinical approach: first, a thorough research on previous mucosal or cutaneous SCC that, in terms of time and location, could act as primary tumors of a salivary SCC metastasis, was conducted. Then, if such a primary tumor was found in the anamnesis, the salivary tumor was considered to be a metastasis.…”