Yolk Sac tumor differentiation in urothelial carcinoma of the urinary bladder: A case report and differential diagnosis

Abstract

Background: Yolk sac tumor (YST) is a germ cell neoplasm that arises predominantly in the gonads, but can also derive from somatic neoplasms in extragonadal locations. These latter cases have been documented in several organs, although reports from the urinary tract are limited. To our knowledge, this is the first report of a bladder urothelial carcinoma with a predominant component of YST differentiation.Case presentation: We present a unique case of a 76-year-old man with a recurrent urinary bladder tumor, initially interpreted as a high grade urothelial carcinoma with glandular differentiation. In the recurrent tumor, diverse histological patterns were identified, including glandular, hepatoid and sarcomatoid. This tumor showed positivity for AFP, GLP3 and SALL4, and negativity for CK7 and EMA. Fluorescent in situ hybridization study showed a polysomic pattern of chromosome 12. All these findings led to the final diagnosis of a YST derived from urothelial carcinoma. Conclusions: YST differentiation should be considered in the differential diagnosis of a high grade urothelial carcinoma, particularly when glandular and other unusual patterns are observed.

Somatic-Type Yolk Sac Tumor Arising as a Predominant Component of Bladder Urothelial Carcinoma

“…Because of the limited number of reported cases, there is no consensus on standard treatment. In the prior case reported by Espejo-Herrera and Condom-Mundó, 3 the patient presented with thoracic mass at presentation, after surgery received chemotherapy cycles with poor response, and developed pulmonary and brain metastasis 9 months following cystectomy. The patient died 11 months after diagnosis.…”

“…Germ cell differentiation has been described in association with somatic tumors arising from several different organ systems 1-4 ; it is well established that urothelial carcinoma may show divergent differentiation, and several variants have been recognized by the 2016 World Health Organization (WHO) classification of urothelial carcinomas. 5 These include but are not limited to squamous, glandular, trophoblastic, neuroendocrine, nested, micropapillary, plasmacytoid, and sarcomatoid variants of urothelial carcinoma.…”

“…Although currently not considered a histologic variant of urothelial carcinoma, yolk sac tumor (YST) differentiation in urothelial carcinoma has been previously reported. 3 Transformation of totipotent malignant cells and genomic instability of tumor cells are believed to be the mechanisms behind the development of nongermline differentiation like yolk sac cells in somatic malignancies. 6,7 Herein, we describe a rare case of YST arising as a predominant component of bladder urothelial carcinoma with likely origin as differentiation of urothelial carcinoma.…”

Clinicopathologic and Molecular Characteristics of Hepatoid Adenocarcinoma of Bladder: a case report

“…Further more, HGUC with solid and papillary arrangements had histological overlaps and might mimic HACD just like this case which was initially misdiagnosed in the rst resection. Primary urothelial carcinoma of bladder with hepatoid features or yolk sac tumor differentiation had also to be distinguished from HACD and a close pathologic sampling and examination was necessary [11].…”

“…Besides, no abnormality was found by systemic imaging examinations which indicated that this patient should suffer a primary bladder cancer instead of secondary or metastatic HAC. Yamada [4] reported a HACD with urothelial carcinoma in situ in the mucosa proximal to the main tumor and more and more urothelial carcinoma with hepatoid features were reported [11,18,19]. Vail [20] reported that 72% of urothelial carcinoma with glandular differentiation had TERT promoter mutations, while primary adenocarcinoma of bladder had no TERT promoter mutations.…”