Placental mesenchymal dysplasia is an increasingly recognizable abnormality. Early cases have been confused with partial hydatidiform mole. Placental mesenchymal dysplasia is probably under-diagnosed because of being an unfamiliar clinical entity and also mistaken for gestational trophoblastic disease due to the similar sonographic findings of two entities. In this report, we describe the clinical, gross, and histopathological findings of placental mesenchymal dysplasia in two cases. The 33-week-preterm baby of a 26-year-old woman with cardiovascular disease and 342 gram placenta and the 19-week fetus with trisomy 21 of a 40 year-old woman were terminated. Macroscopically thick-walled vessels and microscopically hydropic villous with peripherally localized thick-walled vessels without trophoblastic cell proliferation were observed in both cases. These two cases represent a rare placental anomaly that is benign but it is challenging to distinguish placental mesenchymal dysplasia from an incomplete mole. Placental mesenchymal dysplasia should be included in the differential diagnosis of sonographic findings that show a normal appearing fetus and a placenta with cystic lesions. Placental mesenchymal dysplasia is associated with pregnancy-related hypertension. In conclusion, the most important point is "you can diagnose it if you consider it".

Introduction. Neuroendocrine tumors (NETs) develop from the epithelium rich in enterochromaffin cells. NETs most commonly originate from the gastrointestinal and respiratory tract. NETs rarely occur in the urinary bladder.Synchronous tumor is defined as having two different tumors growing at the same time in an organ. NETs are frequently associated with synchronous or metachronous second-primary malignancies. In this paper, we describe a synchronous tumor: a small cell neuroendocrine carcinoma (SCNEC) of the bladder and a Warthin's tumor (WT) of the parotid gland, both of which are highly rare in the literature.Case report. A 79-year-old male patient was admitted to the hospital with gross hematuria and nodular mass involving the wall of the urinary bladder. The bladder neck resection and transurethral bladder resection (TURB) were performed. The tumor consisted of small, uniform, round, and spindled-shaped cells with chromatin dark nuclei and numerous mitotic figures. The cells were immunoreactive for CD56, synaptophysin (diffuse), and keratin (focal). The diagnosis of SCNEC with focal urothelial carcinoma in situ component was established. PET-CT was performed for staging purposes, and it showed a residual/recurrent tumor behind the lumen of the bladder floor and two nodular lesions with metabolic activity in the left parotid. After the biopsy of the parotid gland, it was diagnosed as WT. No metastasis of SCNEC was found at the time of diagnosis, and the patient received four cycles of induction chemotherapy (Etoposide combined with carboplatin chemotherapy) followed by chemoradiotherapy. Conclusion.In this case report, an extremely rare case of primary SCNEC of the bladder with synchronous of the parotid gland is presented, along with a discussion on the clinical presentation, immunohistochemical and cytomorphological characteristics, management, biological behavior, and prognosis.