Kiliaki, Shangwe

ABSTRACT Malignant pleural mesothelioma is a rare and aggressive malignancy associated with poor prognosis. Although it typically spreads through local invasion, distant metastasis to the gastrointestinal tract is uncommon, and colonic involvement is particularly rare. We report a case of metastatic pleural mesothelioma presenting as ulcerated submucosal nodules in the colon. The patient had previously elected active surveillance for known malignant pleural mesothelioma because of poor performance status and multiple medical comorbidities. Approximately 18 months after diagnosis, he was hospitalized with rectal bleeding and diarrhea. Colonoscopy revealed ulcerated submucosal nodules within the colon, and histopathologic evaluation of biopsy specimens demonstrated colonic mucosa infiltrated by malignant mesothelioma. Systemic therapy was not recommended for bleeding control given the patient's overall clinical condition. Management consisted of supportive care, including one packed red blood cell transfusion and serial hemoglobin monitoring. While prior reports describe colonic metastases presenting as polyps or intussusception, this case highlights an atypical manifestation of mesothelioma involving ulcerated submucosal colonic nodules. Recognition of this rare presentation may aid clinicians evaluating gastrointestinal bleeding in patients with mesothelioma.

Drug-induced immune thrombocytopenia is an isolated thrombocytopenia caused by accelerated platelet destruction from drug-dependent, platelet-reactive antibodies. Heparin-induced thrombocytopenia is the most common drug-induced immune thrombocytopenia. Common implicated antibiotics for drug-induced immune thrombocytopenia include ceftriaxone, trimethoprim–sulfamethoxazole, vancomycin, and penicillin. The platelet nadir can be less than 20 × 10 (9)/L and typically occurs within 1 to 2 weeks of exposure to the inciting drug. Although rare, drug-induced immune thrombocytopenia can be fatal. Diagnosis is made by excluding other causes of thrombocytopenia. Laboratory testing for drug-dependent antiplatelet antibodies is often helpful but not required. Thrombocytopenia typically improves within 1 to 2 days of drug discontinuation and platelet count returns to normal within a week. Identifying and discontinuing the implicated medication is key to prevention of serious complications. A patient case of drug-induced immune thrombocytopenia is described after initiation of empiric piperacillin–tazobactam for refractory right foot cellulitis in the setting of right fourth toe diabetic ulcer.