Dermatitis Herpetiformis: Rare Cutaneous Manifestation of Colon Adenocarcinoma

Excerpt

A previously healthy mildly obese 72-year-old Caucasian male with well-controlled type II diabetes presented with a 2-month history of a pruritic papulovesicular rash on the extensor surface of the forearms. Skin punch biopsy showed subepidermal multilocular bullous lesions with edema and neutrophils (Fig. 1). Direct immunofluorescence showed dense granular deposits of IgA in the basement membrane and at the tips of dermal papillae, consistent with the diagnosis of dermatitis herpetiformis (DH) (Fig. 2). The patient did not have any gastrointestinal symptoms, and celiac disease serology including anti-endomysial antibodies and anti-tissue transglutaminase IgA and IgG were negative. The patient did not have any significant improvement in skin lesions on dapsone and gluten-free diet. Six months later, the patient presented with acute onset of right-sided abdominal pain, generalized weakness, anorexia, 25-lb weight loss, and several episodes of melena with iron deficiency anemia. A CT scan of the abdomen showed focal colonic wall thickening and a 5.5-cm hepatic flexure pericolonic fluid collection containing air, which was suggestive of focal perforation with a pericolonic abscess. Multiple enhancing liver lesions were noted which were suspicious for metastatic disease. Lymphadenopathy was noted in the right upper abdomen, involving the portacaval, periportal, and celiac axis regions. The largest lymph node, located in the portacaval region, measured up to 3.2 cm. Colonoscopy 3 years prior was normal. Carcinoembryonic antigen level was elevated at 414. Due to risk of perforation, colonoscopy was delayed pending image-guided biopsy. Biopsy of the liver lesions revealed poorly differentiated adenocarcinoma. Subsequent colonoscopy showed a 9-cm friable, ulcerated, partially obstructing mass extending from the hepatic flexure to the proximal transverse colon (Fig. 3). Endoscopic mucosal biopsies were consistent with poorly differentiated adenocarcinoma. Immunohistochemistry was positive for CK7, mucin, and CK20 and negative for CDX2, TTF-1, chromogranin, synaptophysin, PSA, and PAP. The patient's clinical condition deteriorated rapidly, and he passed away 1 month following the diagnosis of metastatic colon cancer.

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