Gastrointestinal: Anterior mediastinal colonic interposition on F‐18 FDG PET/CT imaging

Abstract

A 45-year old man had a history of dystrophic epidermolysis bullosa (EB) with distal right upper extremity amputation, esophagectomy and anterior mediastinal colonic interposition. He had a recent EB complication of cutaneous squamous cell carcinoma with biopsy proven right axillary nodal metastasis. F-18 FDG PET/CT showed the tracer-avid right axillary metastasis, benign features of brown adipose tissue of bilateral supraclavicular regions and reactive left axillary nodal uptake (based on subsequent tissue sampling). The PET/CT exam is mostly remarkable for the diffusely prominent tracer uptake by the colonic interposition and remainder of the colon (fig. 1 a & b) with corresponding retrosternal location of the colonic interposition on chest radiograph and chest CT (Fig. 1 c & d). Epidermolysis bullosa (EB) represents a group of skin diseases, with different phenotypes, characterized by blistering lesions of the dermal-epidermal basement membrane. EB may also target the epithelial-associated tissues such as external eye, upper airways, gastrointestinal tract especially esophagus, and genitourinary tract with potential development of skin malignancy such as squamous cell cancer and melanoma. Our patient had the colonic interposition procedure secondary to EB-induced esophageal lesions and stenosis. The colonic interposition procedure, with relatively high postoperative morbidity and mortality, is usually a second option following esophagectomy when the first option of gastric pull-through is not possible due to existing gastric lesions or other clinical and anatomic conditions. The colon interposition procedure may re-locate the right or left colon in the anterior mediastinal, posterior mediastinal or subcutaneous position. A comprehensive meta-analytic review showed that the most optimal and safest colonic conduit with lowest surgical morbidity and mortality is the left colonic interposition in the retrosternal/anterior mediastinal location. The diffusely prominent F-18 FDG PET/CT features of the colonic interposition and remainder of the colon may be related to our patient’s subsequent inflammatory involvement occurring through the clinical course of EB. Contributed by KN Huynh and BD Nguyen Department of Radiology, Mayo Clinic Arizona, Scottsdale, Arizona, USA Figure 1 (a & b) Anterior and posterior maximum intensity projection PET images showing the diffusely prominent tracer uptake features of the anterior mediastinal colon interposition (arrowheads) and colon within the abdomen and pelvis. (c & d) Corresponding features of the anterior mediastinal colonic interposition on lateral chest radiograph and sagittal chest CT (arrowheads). doi:10.1111/jgh.14907