Unusual clinical presentation of cutaneous malignant melanoma metastatic to the parotid gland; Initially discovered by fine needle aspiration: Case report and review of literature

Abstract

We report a case of malignant melanoma (MM) metastatic to the parotid gland, initially discovered on fine needle aspiration (FNA). The patient presented with a mass in the parotid gland area with previous history only significant for prostatic carcinoma. The initial FNA impression was melanoma. The smears were hypercellular with bloody necrotic background. The cells were epithelioid with mild nuclear atypia. Discrete cytoplasmic pigmentation was seen. No lymphoglandular bodies were noticed. Fragments of benign salivary gland were also identified. The cytological diagnosis of MM triggered onsite thorough physical examination for potential primary, where a scalp pigmented lesion was discovered hidden by overlying covering hair. Our differential diagnosis included melanoma, metastatic carcinoma, and lymphoma. Further work up for melanoma with S100, HMB45, and Mart 1 confirmed our top differential diagnosis. We emphasize thorough physical examination in such circumstances, and the importance of onsite evaluation guiding clinicians looking for primary.

Metastatic Malignant Melanoma of Parotid Gland with a Regressed Primary Tumor

“…More than 75% of parotid metastases are believed to spread into the intraparotid lymph nodes of a nearby malignancy. The parotid gland is known to function as a filtering center for lymphatic drainage in the head and neck region [ 7 ]. Some studies have reported facial melanomas with metastasis to the parotis and ipsilateral levels I–IV [ 8 ].…”

Metastases to the parotid glands: An institutional experience

“…Although regional and distant metastatic disease should always be considered, it is well-known that, for the parotid gland, around 80% of metastases are derived from squamous cell carcinomas (SCC) of the head and neck region, followed by cutaneous carcinomas and mucosal melanomas. [4][5][6][7][8] Of note, metastatic carcinomas from the breast, lung, kidney and prostate have also been reported in the parotid gland. [4][5][6][7][8] The submandibular gland is more commonly a site of metastases from these latter distant sites.…”

“…[4][5][6][7][8] Of note, metastatic carcinomas from the breast, lung, kidney and prostate have also been reported in the parotid gland. [4][5][6][7][8] The submandibular gland is more commonly a site of metastases from these latter distant sites.…”

“…The morphological distinction between a primary salivary malignancy and a metastasis is highly relevant, because of their divergent therapy and prognosis. [1][2][3][4][5][6][7][8] In a paper by Seifert et al, the authors analysed the files of a Salivary Gland Register, finding 10,944 cases collected between 1965 and 1985. 9 Their series included 108 metastatic tumours to the salivary glands (both parotid and submandibular glands), with 43.5% localised in the parenchyma of the parotid gland, of which 57% were localised to intraparotid lymph nodes.…”

FNA biopsy of secondary nonlymphomatous malignancies in salivary glands: A multi‐institutional study of 184 cases

“…Various hematopoietic and lymphoid malignancies, including lymphomas, constitute a significant portion of SMSGs, with a reported incidence of up to one‐third of all SMSGs . Metastatic carcinomas from sites in the breast, lung, kidney, thyroid, liver, and stomach have also been reported in several small case series and in single‐case reports of SMSG …”