Lipid-Rich Variant of Urothelial Carcinoma Presenting as the Dominant Morphology in a Recurrent Tumor After Local Therapy

Abstract

Patient: Male, 61Final Diagnosis: Urothelial carcinoma • lipid-rich variant • metastaticSymptoms: HematuriaMedication: —Clinical Procedure: Transurethral resection of bladder tumour (TURBT)Specialty: UrologyObjective:Rare co-existance of disease or pathologyBackground:The lipid-rich variant is a rare and aggressive type of urothelial carcinoma (UCa), with less than 40 cases reported in the literature. This variant usually presents as an advanced-stage primary tumor.Case Report:We report the case of a 61-year-old man with previous history of T1 high-grade conventional urothelial carcinoma treated with local therapy. The patient later presented with a new 6.5-cm exophytic bladder mass. Histopathological examination revealed a T2 urothelial carcinoma of the lipid-rich variant. Retrospective review of the previous biopsies confirmed conventional high-grade urothelial carcinoma, but scattered rare individual or small clusters of cells that resemble the lipid-rich variant urothelial carcinoma were also noted.Conclusions:The findings in this case suggest that the differential sensitivity of conventional urothelial carcinoma to local therapy may have allowed the lipid-rich variant to predominate in the recurrence. Pathologists should be aware of the lipid-rich variant of urothelial carcinoma. The prognostic significance of rare lipoblast-like cells among predominantly conventional urothelial carcinoma may requires further study.

Histologic Variants of Urothelial Carcinoma: Morphology, Molecular Features and Clinical Implications

“…The lipid-rich variant of urothelial carcinoma is extremely rare, with fewer than 40 cases reported [70]. Lipid-rich UC is characterized by eccentrically placed nuclei and clear cytoplasmic vacuoles resembling large lipoblasts or signet-ring cells [71].…”

“…Lipid-rich UC is characterized by eccentrically placed nuclei and clear cytoplasmic vacuoles resembling large lipoblasts or signet-ring cells [71]. Tumors with this morphology are usually comprised of 10-50% lipid-rich morphology mixed with either conventional UC or other variants of UC [70]. The majority of neoplastic cells have nuclei of intermediate nuclear grade with occasional pleomorphism [72].…”

“…The behavior of lipid-rich morphology is not well understood, however it appears to be associated with a poor prognosis [70]. It tends to present as an advanced stage high-grade UC [72].…”