Endocrine Abstracts

JOINT38

Introduction: Most neuroendocrine neoplasms are indolent and slow-growing tumors, and given the rather slow progress, some lesions are incidentally discovered as metastatic deposits rather than primary masses. Neuroendocrine tumors of unknown primary site are not so uncommon in the clinical practice and may constitute 12–22% of NEN patients. In these cases, a biopsy is often taken to allow the pathologist to identify the tumor type and possibly the primary tumor site via microscopic examination. Neuroendocrine tumors are classified according to histologic differentiation and grading system, with low-grade, well-differentiated tumors having a more indolent course, while high-grade, poorly differentiated neoplasms are rapidly growing and aggressive, which are closely related to clinical presentation and prognosis.

Case presentation: A 74-year old female hospitalized at internal medicine service due to difficulty in breathing during minor physical exertion, thoracic-abdominal discomfort, edema of the inferior sides, after exclusion of pulmonary thromboembolism with pulmonary angio-CT and acute coronary syndrome in emergency department. Abdominal echo raised the suspicion of cholecystic tumor with multiple hepatic metastases. Subsequent examinations with contrast CT and MRI abdomen, EGD and colonoscopy result in multiple secondary hepatic lesions and cholecystic calculi. CT-guided biopsy and immunohistochemical stain of the liver mass showed poorly differentiated small cell carcinoma with stain positive for PanCK+, Chromogranin+, Ki67 70%, CD56+. Since all the performed examinations were not able to identify a primary source of the tumor, after the oncological evaluation chemotherapy treatment with cisplatinium and etoposide for stage IV small cell NET of unknown primary site with metastasis to liver was recommended. Given the extent of the disease, the patient chose palliative treatment

Conclusions: In cases of neuroendocrine tumors with well-differentiated cells, more detailed diagnostic examinations are performed to find the primary site, with the goal of performing surgical intervention or starting systemic therapy depending on location. Location of primary site is also important in determining the prognosis of neoplasia. In the case of poorly differentiated neoplasms, detailed diagnostic investigations to identify the primary source do not affect the prognosis of the disease. Poorly differentiated neuroendocrine neoplasms, including small cell NET, are treated with platinum based agents regardless of where the primary site is located. In the case of poorly differentiated neoplasms.