Metastatic urothelial carcinoma to the mandible

Abstract

Urothelial carcinoma (UC) is the second most common malignancy of the genitourinary tract and sixth most common malignancy in the US. It predominately affects patients in the seventh decade with a male predilection. Presenting symptoms may include hematuria, infection, and urinary obstruction. First-line treatment of invasive UC consists of surgical resection with platinum-based chemotherapy. Promising roles for immunotherapy and targeted therapy have also emerged. We herein describe a 68-year-old female who presented for evaluation of long-standing pain involving her anterior mandible. Radiographs revealed an ill-defined radiolucency in the region of #22 to #27. Histologic examination of a biopsy taken from the #23 periapex showed sheets and nests of atypical epithelial cells with abundant eosinophilic to vacuolated cytoplasm and central nuclei. In several areas, the cells were markedly discohesive and exhibited prominent hobnailed configurations. On immunohistochemical analysis, the neoplastic population was reactive for AE1/3, CK7, and CK20. Follow-up discussion with the patient's physician revealed a history of invasive high-grade urothelial carcinoma diagnosed one year prior and treated with neoadjuvant chemotherapy followed by cystectomy. The prior specimens were reviewed and showed morphologic similarities to the mandibular biopsy, supporting a diagnosis of metastatic urothelial carcinoma in the latter. The patient subsequently underwent second- and third-line treatment but has continued to show progression of her disease. Metastasis to the oral cavity is an uncommon occurrence that accounts for only 1% of all oral malignancies. The majority of cases occur in the setting of disseminated disease with a known primary, although a small percentage of oral metastases represent the initial manifestation of occult disease. Metastasis of UC to the oral cavity is exceedingly rare with less than 20 cases reported in the literature. However, knowledge of the morphological and immunohistochemical hallmarks of this malignancy can aid in directing the diagnostic workup, thereby facilitating timely management.