Yu Ryan, Salama Samih, Alowami Salem
*Department of Pathology and Molecular Medicine, McMaster University, Hamilton Health Sciences, Hamilton, Ontario, Canada; and †Department of Pathology and Molecular Medicine, McMaster University, St Joseph's Healthcare Hamilton, Hamilton, Ontario, Canada.
Am J Dermatopathol. 2015 Mar;37(3):e26-30. doi: 10.1097/DAD.0000000000000073.
Mucoepidermoid carcinoma (MEC) is a malignant glandular epithelial neoplasm that most commonly arises in the major salivary glands. Primary cutaneous MEC is very rare. There is a particular diagnostic challenge in determining the primary site of MEC when it is found in skin overlying the parotid gland. Attention to a combination of morphologic findings may be helpful. However, differentiation of primary cutaneous MEC from secondary cutaneous involvement by a parotid MEC may be unnecessary once the parotid gland is infiltrated. We report the case of a 54-year-old male with a 2-cm asymptomatic mass overlying the right parotid gland, which was managed by excision of the affected skin, right total parotidectomy, and right neck dissection. Histopathologic and immunohistochemical findings were consistent with a cutaneous intermediate-grade MEC. Postoperative radiotherapy was deferred. The patient showed no evidence of recurrence or metastasis at 2 months before self-discontinuing follow-up. To our knowledge, this is only the second reported case of MEC involving the parotid gland, but of overlying primary cutaneous origin.
黏液表皮样癌（MEC）是一种恶性腺上皮肿瘤，最常发生于大唾液腺。原发性皮肤黏液表皮样癌非常罕见。当在腮腺上方的皮肤中发现黏液表皮样癌时，确定其原发部位存在特殊的诊断挑战。关注形态学表现的综合情况可能会有所帮助。然而，一旦腮腺受到浸润，区分原发性皮肤黏液表皮样癌与腮腺黏液表皮样癌继发皮肤受累可能就没有必要了。我们报告一例54岁男性病例，其右侧腮腺上方有一个2厘米无症状肿块，通过切除受累皮肤、右侧全腮腺切除术和右侧颈部清扫术进行治疗。组织病理学和免疫组化结果与皮肤中级黏液表皮样癌一致。术后放疗推迟。在患者自行停止随访前2个月，未发现复发或转移迹象。据我们所知，这是第二例报告的累及腮腺但起源于腮腺上方原发性皮肤的黏液表皮样癌病例。
