# Catastrophic antiphospholipid syndrome with eosinophilia mimicking hypereosinophilic syndromes with disseminated intravascular coagulation: a case report

## TL;DR

A rare case of catastrophic antiphospholipid syndrome with high eosinophil levels was mistaken for other eosinophil-related diseases, highlighting the importance of testing for antiphospholipid antibodies in similar cases.

## Contribution

This is the first reported case of catastrophic antiphospholipid syndrome with eosinophilia, expanding differential diagnosis for eosinophilia with coagulopathy.

## Key findings

- Eosinophilia can accompany catastrophic antiphospholipid syndrome and mimic other eosinophil-associated disorders.
- Plasma exchange and rituximab successfully treated the patient, who remained in remission for 4 years.
- Antiphospholipid antibodies turned negative after treatment, suggesting a causal link to the condition.

## Abstract

Catastrophic antiphospholipid syndrome is a rare variant of antiphospholipid syndrome where the presence of antiphospholipid antibodies and systemic inflammation leads to the rapid onset of multifocal thrombosis. Eosinophilia is known to accompany conditions such as allergy, parasite infection, malignancy, or autoimmune diseases; however, catastrophic antiphospholipid syndrome with eosinophilia has not been reported and its clinical influence remains unknown. We describe the first case of probable catastrophic antiphospholipid syndrome with eosinophilia, which mimicked eosinophil-associated disorders such as hypereosinophilic syndromes or eosinophilic granulomatosis with polyangiitis with disseminated intravascular coagulation, adding a new aspect of differential diagnosis of eosinophilia.

A 46-year-old previously healthy Japanese man presenting with fever, abdominal pain, and skin lesions with pruritus showed marked eosinophilia, thrombocytopenia, and coagulopathy. A dynamic contrast-enhanced computed tomography scan of the abdomen showed some nonenhancing lesions in both lobes of the liver and the portal vein thrombosis. Upper gastrointestinal endoscopy showed gastric erosions, and lower gastrointestinal endoscopy revealed transverse colon and cecum ulcers. Common causes of eosinophilia including allergy, infection, and medication were not detected. He was initially suspected with hypereosinophilic syndromes or vasculitis such as eosinophilic granulomatosis with polyangiitis complicated by disseminated intravascular coagulation, and was treated with prednisone and thrombomodulin from hospital day 4 after bone marrow examination and the biopsies of the skin, stomach, and colon; however, these examinations excluded neoplastic hypereosinophilic syndromes and vasculitis. Later examination revealed positive antiphospholipid antibodies including lupus anticoagulant, anticardiolipin antibodies immunoglobulin G, and anticardiolipin β2-glycoprotein 1 complex antibodies. He was complicated by colonic perforation and bilateral adrenal hemorrhage on day 10. Histopathology of the resected colon and liver biopsy confirmed arterial and venous small-vessel thrombosis and microthrombi, leading to the diagnosis of probable catastrophic antiphospholipid syndrome. He was successfully treated with plasma exchange and rituximab. He has been in remission of catastrophic antiphospholipid syndrome for 4 years, and his antiphospholipid antibodies have been negative post-rituximab treatment. His eosinophil count has been between normal to slightly increased, possibly due to the chronic adrenal insufficiency.

Our case shows that eosinophilia can accompany catastrophic antiphospholipid syndrome, and this can mimic eosinophil-associated disorders with disseminated intravascular coagulation. Identifying antiphospholipid antibodies is important for differential diagnosis when treating unexplained eosinophilia, thrombocytopenia, and thrombosis.