S2748 A Rare Case of Esophageal Carcinoma Cuniculatum Resulting in a Broncho-Esophageal Fistula and Requiring Both Esophageal and Endobronchial Stenting

Introduction: Carcinoma cuniculatum (cc) is a rare and often indolent histologic variant of well-differentiated squamous cell carcinoma. We describe a unique case of CC of the esophagus resulting in a complex broncho-esophageal fistula requiring esophageal and endobronchial stenting. Case Description/Methods: The patient is a 67-year-old woman with HIV on therapy who presented with significant unexplained weight loss. A positron emission tomography scan showed FDG avid esophageal mass with presumed radiographic metastatic lesions to the mediastinal lymph nodes. Multiple endoscopic mucosal, EUS-guided and bronchoscopic biopsies of the mass and mediastinal lymphadenopathy proved non-diagnostic yielding occasional squamous hyperplasia and atypia. A broncho-esophageal fistula was later discovered involving the left mainstem bronchus, requiring placement of esophageal and endo-bronchial stents. The case underwent extensive multidisciplinary review with GI, pulmonary, pardio-thoracic and HIV services, and the patient’s operative risk was deemed prohibitively high. Dual stenting allowed for successful palliation of the fistula with resumption of oral intake and hospital discharge. The patient eventually expired after she experienced an acute episode of hemoptysis, suspected to be related to the fistula progression with erosion into a pulmonary vessel. Ultimately the diagnosis was established via autopsy with histopathologic findings consistent with esophageal CC (Figure 1). Discussion: CC was first described by Ayrd et al (1) in 1954 as a histologic variant of well-differentiated squamous cell carcinoma, with less than 10 reported cases so far (2). It frequently poses a diagnostic challenge: as in our case, in almost all prior reported cases a definite diagnosis could not be made before esophagectomy (2). The case was further complicated by the development of a complex broncho-esophageal fistula requiring both esophageal and endobronchial stenting. Successful palliation of the broncho-esophageal fistula illustrates the importance of a multidisciplinary approach in the management of this uniquely aggressive case of CC. References: 1. Ayrd I, Johnson HD, Lennox B, et al. Epithelioma cuniculatum: a variety of squamous carcinoma peculiar to the foot. Br J Surg 1954;42:245–250. 2. Landau M, Goldblum JR, DeRoche T, et al. Esophageal carcinoma cuniculatum: report of 9 cases. Am J Surg Pathol 2012;36(1):8-17.Figure 1.: A,B: Left bronchial metal stent covers bronchoesophageal fistula. C,D: 4.1 x 3.8 x 0.6 cm esophageal mass surrounds the 1.7 x 0.9 cm bronchoesophageal fistula. E,F, G: HandE sections of the distal esophagus and gastroesophageal junction show clusters of neoplastic squamous cells displaying endophytic growth pattern, moderate nuclear pleomorphism, increased mitotic activity and squamous pearl formation. H: Esophageal endoscopic images of broncho-esophageal fistula. I: after stent placement. J, K: Bronchoscopic images of the L main endobronchial defect as viewed from the distal trachea (J) and after stent placement (K).