A 57‐year‐old Hispanic male presented with altered mental status associated with progressive weakness over the preceding 2 months. On admission, he was found to have hypercalcemia, thrombocytopenia, hemolytic anemia and acute renal failure without evidence of DIC, A peripheral smear revealed numerous schistocytes. A presumptive diagnosis of idiopathic TTP was made. Plasma exchange and prednisone were initiated. However despite plasma exchange, his thrombocytopenia did not improve and his ADAMTS‐13 activity was normal. Further imaging showed possible metastatic disease with MRI brain showing an enhancing right intraconal lesion, CT chest with pulmonary nodules, CT abdomen with liver nodules, and an MRI showing diffuse metastatic lesions. Bone marrow biopsy was performed and revealed metastatic medullary thyroid carcinoma. Unfortunately, the patient was not a candidate for chemoradiation given his poor functional status, and he was referred to hospice care.
Disseminated malignancy in the absence of DIG can cause a microangiopathic hemolytic anemia with thrombocytopenia, mimicking idiopathic TTP. Microvascular tumor emboli are the presumed etiology of The microangiopathic hemolytic anemia with thrombocytopenia. There have been 29 documented cases of disseminated malignancy initially diagnosed as idiopathic TTP. A wide variety of malignancies can mimic TTP. Fourteen different malignant disorders were described in the 29 documented cases. One study by Francis et al. (2007) found 10 of 351 patients initially diagnosed with TTP actually had disseminated malignancy. When these patients were compared to patients with idiopathic TTP, they had longer duration of symptoms prior to presentation and their symptoms usually included respiratory complaints. The patients with malignancy usually had higher LDH levels, but there was no difference in ADAMTS‐13 activity. The patients with disseminated malignancy had a higher mortality and were less likely to respond to plasma exchange when compared to the patients with Idiopathic TTP.
Microangiopathic hemolytic anemia with thrombocytopenia can be caused by an occult disseminated malignancy, and it can be Initially misdiagnosed as idiopathic TTP. Clinicians should maintain a high index of suspicion for malignancy as potential cause of microangiopathic hemolytic anemia especially if patients do not respond to plasma exchange therapy or who have atypical features. Failure to recognize this TTP mimic may lead to a delay in starting chemotherapy for the underlying malignancy and lead to a prolongation of unnecessary plasma exchange.
R. Poteet, none; P. Gravel, none.