Background. Metastasis to parotid gland occurs mostly from skin cancers of the head and neck region. Metastatic neuroendocrine tumors to the parotid gland are rare and not well studied so far. In this study, we undertook a retrospective review of secondary neuroendocrine tumors of the parotid diagnosed in our institution. The most common entities, primary tumor locations, their clinical presentations and histopathological features were analyzed. Methods. Cases of secondary neuroendocrine tumors to parotid diagnosed from August 1995 to Jan 2021 were retrieved from our institution's pathology databases, and their clinicopathological features were reviewed. Results. About 29% (120 of 420 cases) of parotid neoplasms were malignant, including 70 cases of parotid primary malignant tumors and 50 cases of metastases to parotid glands. Among metastatic tumors to the parotid glands, squamous cell carcinoma and melanoma of the head and neck region together accounted for about 78% of the cases. Only 11 of 50 metastatic tumors to the parotid were neuroendocrine carcinomas (22%). The most common primaries were poorly differentiated neuroendocrine carcinoma of lung (5 of 11 cases), including 4 cases of small cell carcinoma and one case of large cell neuroendocrine carcinoma. The second most common secondary tumor was Merkel cell carcinoma (4 of 11 cases, 36%) including one case of direct invasion from overlying skin. Medullary carcinoma of the thyroid comprised the rest of the metastases to the parotid (2 of 11 cases, 18%). Conclusion. Our results show that metastatic neuroendocrine carcinomas to the parotid gland account for about 22% of all metastatic tumors to the organ. Lung is the most common primary neuroendocrine carcinoma location. It is not uncommon for metastatic neuroendocrine carcinoma to present as the first sign of systemic clinical manifestation. Merkel cell carcinoma is the second most common entity that metastasizes to parotid, followed by medullary carcinoma of the thyroid.

Routine histopathological examination of hernia sac in adults remains a controversial topic. We undertook a retrospective study to assess possible clinical benefits of pathological examination of hernia sac specimens. Our pathology database between 1992 and 2020 was searched for adult specimens submitted as hernia sac. The clinical and pathological data of patients with abnormal histopathological findings were reviewed. There were 5424 hernia sac specimens (3722 inguinal, 1625 umbilical, and 77 femoral), 32/5424 (0.59%) with malignancies (28 epithelial and 4 lymphoid) and 25/32 were located in the umbilical region. Twelve out of twenty-five malignancies (48%) presented as primary clinical manifestations of the diseases (5 GI tract carcinomas, 5 gynecological tract carcinomas, and 2 lymphoid neoplasms); and 13/25 (52%) specimens were involved by previously known tumors (8 gynecological carcinomas, 3 colon carcinomas, 1 breast carcinoma, and 1 lymphoma). Among the 7 inguinal hernia sacs with malignancies, 3 (42.9%) were primary presentations of the tumors (2 prostatic carcinomas, 1 pancreatic carcinoma), and 4 (57.1%) were previously known tumors (2 ovarian carcinomas, 1 colon carcinoma, 1 lymphoid). Benign lesions were 12/5424 (0.22%), including 7 adrenal rests, 4 endometriosis, and 1 inguinal sarcoidosis. The incidence of hernia sacs with malignancies was 32/5424 (0.59%), most commonly from nearby organs in gynecological tract. However distant metastases from breast were also present. Near half of the hernia sac with malignancies (15/32, 47%) presented as the first clinical manifestation. Routine histopathological examination of hernia sac in adults is recommended, since it may provide important clinical information.

Metastatic spread is the single most significant predictor of poor survival in breast cancer. Some of the most common metastatic sites are the bones, lungs, liver, brain, and peritoneal cavity. Clinically metastatic breast cancer to the gynecologic tract is usually asymptomatic and diagnosed as an incidental finding during a histologic examination of gynecologic specimens resected for other reasons. Cases of metastatic breast cancer to gynecologic organs diagnosed from August 1995 to January 2021 were retrieved from our institution’s pathology databases, and their clinicopathologic features were reviewed. The most common site of metastasis was the ovary which was involved in about 79% (22 of 28 cases) of metastases to the gynecologic tract. Clinically, only 8 cases (36%) presented with ovarian mass detected in imaging studies and the rest of the cases were all incidental findings. Among ovarian metastasis, 59% of cases were invasive lobular carcinoma and 41% were invasive ductal carcinoma. In 5 cases, metastatic breast cancer was found in the endometrium, including 2 cases with endometrial metastasis only and 3 cases with multiple gynecologic organs involved. Metastatic breast cancer rarely involved the lower gynecologic tract, with only 7% vaginal metastasis and 4% found in the vulva. The absolute majority of metastatic breast cancer outside of the ovaries were lobular carcinoma (88%). Most of the metastatic breast carcinomas were positive for estrogen receptor on immunohistochemistry (27 of 28 cases, 96%). Her-2/neu immunostaining was positive in 4 cases only (14%). Metastatic breast cancer needs to be distinguished from gynecologic primary neoplasms and metastatic tumors from adjacent urinary and GI tracts. A careful review of the patient’s history and adequate immunohistochemistry panel are helpful to render the diagnosis.

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Endolymphatic sac tumors are extremely rare, locally aggressive neoplasms that arise from the endolymphatic sac or duct, primarily in the intraosseous portion. These neoplasms show diverse histomorphological architectures and despite a bland cytologic appearance, can locally recur. Although the clinicopathological and radiological features of this entity are well characterized, the literature on cytological features is extremely sparse. Herein, we describe the cytological features of the endolymphatic sac tumors and discuss the relevant differential diagnoses.