Since the 19th century, neuroendocrine neoplasms (NEN) have been
identified. Right up to the present day, the nomenclature is still under debate
reflecting the heterogeneity of these tumors. Although some of them are slow
growing, some can be fearfully aggressive and may develop in almost any
organ of the abdomen, thorax, neck, skin, and gonads. The most commonly
observed sites of NEN are the lung and the gastroenteropancreatic system
(GEP), where more than 50 entities have been observed. In case of a NEN
of unknown primary tumor, the histopathological diagnostic workup includes
immunohistochemistry for chromogranin A and synaptophysin, followed by
specific tissue markers. Clinical presentation is very diverse, depending on
the primary site and functionality of the tumor. In the case of the GEP-NEN,
the main symptoms are abdominal pain, diarrhea, weight loss, gastrointestinal
bleeding, or bowel obstruction. The presence of neuropsychiatric symptoms
is not insignificant in this group of tumors. The authors report a case of a
51-year-old man who sought medical attention because of a three-month
history of a consumptive disease. The diagnostic workup disclosed a diffuse
nodular infiltration of the lungs, hypokalemia, and hypercalcemia in a cachectic
patient. The clinical investigation could not proceed because of an infectious
intercurrence, which led to the fatal outcome. Autopsy findings showed a
diffuse metastatic NEN. The primary tumoral site could not be demonstrated
with the available immunohistochemical panel.
