Introduction
Neuroendocrine neoplasms originating in the urinary bladder are
exceptionally uncommon. According to the latest WHO/ISUP classification
from 2016, there are four recognized types of neuroendocrine neoplasms
found in the urinary bladder: small cell neuroendocrine carcinoma, large
cell neuroendocrine carcinoma, well-differentiated neuroendocrine tumor,
and paraganglioma. Small cell neuroendocrine tumors make up less than
1% of malignant bladder tumors, while large cell neuroendocrine tumors
represent an even rarer subset [1-3].
In bilharzia-endemic areas, schistosomiasis is a common infection, and
it is recognized as a risk factor for squamous cell carcinoma of the
bladder. Research indicates that schistosomiasis has also been linked to
various other histotypes, such as neuroendocrine tumors of the
gastrointestinal tract [4,5]. Admixing of both small cell
neuroendocrine and large cell neuroendocrine tumors is rare. However,
such a coexistence has been described in a very few patients, but it has
not been linked to schistosomiasis [6,7].