PB0337 - Occult Cervical Cancer-induced Refractory Thrombotic Thrombocytopenic Purpura in a Renal Transplant Patient with Low-level Cytomegalovirus Viremia: a Case Report

Background: Cancer infrequently causes TTP, and was early recognized among mucinous type of malignancies. CMV can cause TTP and reactivate in the presence of immunocompromised state. Absence of viral load threshold to initiate therapy represents a challenge since low-level viremia is common and may progress to higher viral loads if not treated.

Aims: We aim to report a case of an occult cervical cancer-induced refractory TTP initially attributed to CMV infection in a renal transplant patient, and present the challenges encountered in the management.

Methods: We reviewed the association of cancer and CMV as an etiology of TTP, and performed extensive search of similar cases available in the literature.

Results: A 44-year old female, known renal transplant being treated for rejection with steroids, presented with pallor and pustules on her knee. Examinations showed platelets of 90 x 109/L, 4+ schistocytes, and normal coagulation profile. She was managed as TTP, but ruling out ADAMTS-13 deficiency became difficult due to unavailability of the test upon admission. Treatment commenced immediately with plasmapheresis. Although early investigations were negative, ADAMTS-13 assays obtained after 10 sessions of plasmapheresis were normal, while CMV viral load was low at 161 copies/mL. Kidney biopsy and bone marrow studies were unremarkable. Despite 13 sessions of plasmapheresis, high- dose steroids, and 3 rituximab infusions, TTP remained refractory to treatment. She eventually received cyclophosphamide and improved. During follow up, she complained of menstrual irregularities. Thorough evaluation confirmed the presence of cervical cancer.

Conclusion(s): Cancer can be responsible for the TTP but can be difficult to diagnose, and can present later in the disease course. In our case, CMV was initially thought to be causing the TTP, but the low-level viremia and absence of invasive disease made it highly unlikely. Diagnosis of cervical cancer was not made until much later, emphasizing the need for extensive and repeated evaluation.