Endocrine Abstracts

Oesophageal neuroendocrine tumours (NETs) are much rarer than other GI NETs, the majority showing aggressive behaviour. Amongst these, well-differentiated neuroendocrine tumours, poorly differentiated neuroendocrine carcinomas (NECs), and mixed neuroendocrine-non-neuroendocrine neoplasms can be recognized. A 66-year-old male with no past medical history presented with progressive dysphagia. Upper gastrointestinal endoscopy revealed circumferential narrowing at 33-37 cm with superficial ulceration. Biopsy was suggestive of poorly differentiated squamous cell carcinoma (SCC). Despite seven cycles of neoadjuvant chemotherapy (docetaxel, cisplatin, fluorouracil), a suboptimal response was noted, and tumour progression was seen on repeat endoscopy. Repeat oesophageal biopsy immunohistochemical (IHC) staining revealed cytokeratin, CD56 and chromogranin, and synaptophysin were positive, and p63 was negative. 54-year-old male presented with 3 months of dysphagia. Upper gastrointestinal endoscopy revealed ulcero-proliferative growth at the mid-thoracic oesophagus. On biopsy, a diagnosis of possible poorly differentiated SCC was given. On IHC, CD56 and chromogranin were positive. 63-year-old female being followed up in NET clinic, initial histology suggestive of well-differentiated gastrin-positive oesophageal NET. Noted marked tumour aggressiveness and poor response to chemotherapy. Repeat endoscopy was suggestive of oesophageal SCC. Accurate pathological diagnosis of NETs is challenging due to difficulties in distinguishing NETs/NECs from other poorly differentiated oesophageal neoplasms. NECs have often been misdiagnosed as SCCs due to the co-existence of squamous cell carcinoma and/or adenocarcinoma. Generally, neuroendocrine biomarkers, such as Synaptophysin and Chromogranin, are essential for the diagnosis of NETs. IHC is very useful for identifying typical NET histology and cell differentiation. Immunohistochemistry may prevent confounders with small cell carcinoma and mixed histology. Recognising possible co-existence of neuroendocrine tumours or carcinomas with parent organ malignancy is essential. Variability in tumour behaviour may be an indicator of a dual nature that needs close liaison of endocrine, oncology, and histopathology.