Cutaneous neuroendocrine adenoma: an uncommon neoplasm

68 Ga-DOTATATE Uptake in Well-Differentiated Neuroendocrine Tumor of the External Auditory Canal

ABSTRACT

A 38-year-old woman presented with a 4-month history of left-sided otalgia and otorrhea. Otoscopy revealed a mass in the left external auditory canal causing obliteration. A biopsy was taken, and the diagnosis was consistent with a well-differentiated neuroendocrine tumor. The patient was referred to our department for staging with 68 Ga-DOTATATE PET/CT. Increased radiopharmaceutical uptake was observed in the primary tumor and metastatic lymph nodes.

Neuroendocrine Differentiation of Skin Tumors: A Comprehensive Review

Neuroendocrine differentiation is characterized by endocrine and neuronal features with prominent dense secretory granules and neuropeptides. Neuroendocrine differentiation of skin tumors is of unknown clinical significance. Nonetheless, the acknowledgment of this line of differentiation is important to prevent diagnostic pitfalls and subsequent inappropriate management. This review aims at summarizing the skin neoplasms that can express neuroendocrine markers.

Primary carcinoid tumor in the external auditory canal

A 39-year-old man visited the department of otolaryngology due to an ongoing hearing disturbance that had lasted for 1 year. Temporal bone computed tomography revealed soft tissue density nearly obliterating the left external auditory canal (EAC). The mass was composed of sheets of round tumor cells containing moderate amounts of fine granular cytoplasm and salt and pepper chromatin. Neither mitosis nor necrosis was found. The Ki-67 proliferation index was less than 2%. Cells were positive for CD56 and synaptophysin but negative for chromogranin, cytokeratin (CK) 20, and CK7. Based on these findings, the tumor was diagnosed as a carcinoid tumor, well differentiated neuroendocrine carcinoma, grade 1 (G1) according to current World Health Organization (WHO) classification of head and neck tumors; and a neuroendocrine tumor, G1 according to neuroendocrine neoplasm (NEN)-2018 WHO standard classification. He remained free of local recurrence and metastasis after 20 months of follow up. To date, only six cases of primary NENs in the EAC have been reported. Metastatic tumor should be included in the differential diagnoses. Because of its rarity, the prognosis and treatment have not yet been clarified.

Cutaneous neuroendocrine carcinoma of the external auditory canal: a case report and review of the literature

Cutaneous neuroendocrine carcinoma (cNEC) is rarely seen in the external ear. In this paper, we newly describe a patient with cNEC in his right external auditory canal, followed by a further discussion on the clinical features, diagnosis, and treatments of cNEC of the external ear. A review of the literature showed that cNEC of the external auditory canal generally presents as asymptomatic and that pathology yields the most confirmative diagnosis. A wide resection with adjuvant radiotherapy and chemotherapy is recommended. The overall prognosis of this condition is poor.