The panel of syntaxin 1 and insulinoma-associated protein 1 outperforms classic neuroendocrine markers in pulmonary neuroendocrine neoplasms.

Syntaxin-1 (STX1) is a recently described highly sensitive and specific neuroendocrine marker. We evaluated the applicability of STX1 as an immunohistochemical marker in pulmonary neuroendocrine neoplasms (NENs). We compared STX1 with established neuroendocrine markers, including insulinoma-associated protein 1 (INSM1). Typical carcinoids (n = 33), atypical carcinoids (n = 7), small cell lung carcinomas ([SCLCs] n = 30), and large cell neuroendocrine lung carcinomas (n = 17) were immunostained using tissue microarray for STX1, chromogranin A, synaptophysin, CD56, and INSM1. Eighty-four of eighty-seven (96.5%) NENs showed STX1 positivity. Carcinoids and LCNECs typically presented a combined strong membranous and weak cytoplasmic staining pattern; cytoplasmic expression was predominately observed in SCLCs. The sensitivity of STX1 was 90% in SCLCs and 100% in typical carcinoids, atypical carcinoids, and large cell neuroendocrine lung carcinomas. The overall sensitivity of STX1 in pulmonary NENs was 96.6%, and the sensitivity of the other markers was as follows: chromogranin A (85.2%), synaptophysin (85.2%), CD56 (92.9%), and INSM1 (97.7%). STX1 was found to be an excellent neuroendocrine marker of pulmonary NENs, with sensitivity and specificity surpassing that of classic markers. We propose a panel of STX1 and INSM1 for the routine immunohistochemical workup of pulmonary NENs.

[Large-cell neuroendocrine carcinoma of the lung - challenges of diagnosis and treatment]. / Nagysejtes neuroendocrin carcinoma ­ a kórisme és a kezelés nehézségei.

Small-cell lung carcinoma (SCLC) and the rare large-cell neuroendocrine carcinoma belong to the high grade pulmonary neuroendocrine carcinomas. Making the correct diagnosis and selection of treatment modalities require multidisciplinary meetings due to the morphological overlaps, aggressive behaviour and debated therapeutic guidelines of these entities. A 52-year-old woman was admitted to the hospital because of headache, nausea and tenebrous vision. The CT revealed metastatic tumour mass in the occipital lobe and in the cerebellum. Both tumours were removed and resulted in histological diagnosis of metastatic neuroendocrine carcinoma. Chest X-ray established contrast-enhancing lesion in the left lung. Bronchoscopy was performed and histological examination revealed large-cell neuroendocrine carcinoma. Postoperative skull irradiation and small-cell lung cancer chemotherapy protocol were utilized. Due to atelectasis and progression, chest irradiation was initiated, which was interrupted because of novel brain metastases. Further chemotherapy followed the non-small-cell lung cancer protocol. After 3 months, thoracic progression, brain and disseminated bone metastases were diagnosed. After a 14-month-long therapy, the patient deceased. Large-cell neuroendocrine carcinoma has a poor prognosis, the incidence of brain metastasis is 25-50%. In early stage large-cell neuroendocrine carcinoma, lobectomy is the standard treatment and adjuvant chemotherapy should also be considered. Although the non-small-cell lung cancer chemotherapy protocol is approved widely in the treatment of large-cell neuroendocrine carcinoma, the utility of SCLC scheme has also been suggested. Orv Hetil. 2020; 161(8): 313-319.