The rarest of rare cases within the one thousand faces of atypical carcinoid: Pseudomesotheliomatous manifestation in a pregnant woman

Carcinoid tumors in pregnant women are rare, and there have been no previous studies of atypical carcinoid tumor reported in pregnancy. Also, pseudomesotheliomatous manifestation in atypical carcinoid is an extremely rare finding, there being only two cases reported. Here, we present the first case of pseudomesotheliomatous manifestation of atypical carcinoid in a pregnant woman. Upon image analysis, we found that atypical carcinoids with multiple metastatic lesions can exhibit variability in vascularity and metabolism, resulting in heterogeneous image characteristics among metastatic lesions, even those with identical histology. In addition, even with extensive metastasis, patients can exhibit good performance explained by long‐standing presentation of indolent cancer. We present an extremely rare case of pseudomesotheliomatous manifestation of atypical carcinoid in a pregnant woman, focusing on the image findings and discrepancy between performance status and extensive metastasis. Our case shows that atypical carcinoids with multiple metastatic lesions can exhibit variability in vascularity and metabolism, resulting in heterogeneous image characteristics among metastatic lesions. In addition, even with extensive metastasis, patients can exhibit good performance explained by long‐standing presentation of indolent cancer.