Primary Oral Mixed Neuroendocrine-Non-neuroendocrine Neoplasm (MiNEN): A Rare Case Report and Review of the Literature

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are rare tumors recently characterized by the presence of both neuroendocrine and non-neuroendocrine components within the same tumor tissue. Although MiNEN found their place in the WHO classification for various organs, this composite tumor in the head and neck region remains exceptionally rare. We present a case of primary oral MiNEN in a 64-year-old male located on the left side of lower gingiva. Biopsy raised suspicion of neuroendocrine carcinoma (NEC) and the patient underwent partial mandibulectomy. The resected specimen showed two distinct components of NEC and squamous cell carcinoma (SCC) with the confirmation of immunohistochemical markers. There has been no sign of recurrence nor metastasis 6 years after the surgery. In addition, we have conducted a review of published cases with potential relevance to this entity, resulting in five cases. The diverse terminology reinforces the need for a standardized classification system of oral/head and neck MiNENs.

Oral and Maxillofacial Neuroendocrine Carcinoma: A Systematic Review

The aim of the present study was to integrate the available data published in the literature on oral and maxillofacial neuroendocrine carcinomas concerning the demographic, clinical and histopathological features of this condition. An electronic search with no publication date restriction was undertaken in April 2021 in four databases. Eligibility criteria included reports published in English having enough data to confirm a definite diagnosis, always showing a neuroendocrine marker. Cases originating in the oropharynx, including base of the tongue and tonsils, were excluded. Outcomes were evaluated by the Kaplan-Meier method along with Cox regression. Twenty-five articles (29 cases) from nine different countries were detected. Mean patient age was 56.3 (± 17.5) years, with a slight male predilection. Symptomatology was present in 72.2% of informed cases. Regarding clinical presentation, a non-ulcerated nodule located in the gingiva with a mean size of 3.4 (± 2.0) cm was most frequently reported. Concomitant metastasis was identified in seven individuals. Histopathologically, most neoplasms were of the small cell type, and immunohistochemistry for both epithelial and neuroendocrine differentiation was used in 65.5% cases. Radical surgery was the treatment of choice in almost all cases, with or without adjuvant therapy. Mean follow-up was 20.5 (± 21.2) months, and only four patients developed recurrences. Eleven (44.0%) individuals died due to the disease. Ulcerated lesions were a prognostic factor. This study provides knowledge that can assist surgeons, oncologists, and oral and maxillofacial pathologists with the diagnosis and management of neuroendocrine carcinomas. Our findings demonstrated that the long-term prognosis of this lesion continues to be poor.

Collision tumor of squamous cell carcinoma and neuroendocrine carcinoma in the head and neck: A case report

BACKGROUND

There are many disputes about the definition, diagnosis, therapy, and prognosis of collision tumors.

CASE SUMMARY

We describe a rare patient with a collision tumor consisting of neuroendocrine carcinoma (NEC) and squamous cell carcinoma (SCC) in the nasal cavity and paranasal sinus. She received operation, concurrent chemoradiotherapy, and then two cycles of palliative chemotherapy. Follow-up at 12 mo after diagnosis showed that this patient experienced a complete response with no signs of recurrence or metastasis. A literature review of previous 26 cases diagnosed with collision tumor of NEC and SCC in the head and neck was also undertaken.

CONCLUSION

It is challenging to manage collision tumors because there are two morphologically and etiologically distinct tumors. Well-designed multimodality therapy including surgery and chemoradiotherapy might lead to a long survival in these patients.