Sparganosis presenting as a subcutaneous mass of the thigh

Introduction

Sparganosis is a rare zoonotic disease in humans. It is caused by infection of the third-stage plerocercoid larva (sparganum) of pseudophyllidean cestodes of the genus Spirometra. The most common clinical manifestation is subcutaneous sparganosis, while cerebral and ocular sparganosis are more scarce [1, 2]. Most cases were reported in Eastern and Southeastern Asia [2, 3]. This zoonosis is almost neglected in Europe [4]. Histopathologically, identification of the worms is mandatory to make accurate diagnosis and treatment. Therein, we report a typical case of subcutaneous sparganosis.

Case report

A 61-year-old Taiwanese woman presented to our hospital with left thigh mass for 2 years. She had underlying diseases of type 2 diabetes mellitus and hyperlipidaemia. She also had a history of thyroid cancer and received surgical treatment. Two years earlier, she noted a lump at her left thigh. The mass was irregular without surrounding erythema. She went to a local dermatological clinic for help, and she was transferred to the Department of Plastic Surgery of our hospital. Physical examination noted a 4.5 x 3.0 cm mass at left thigh with mild tenderness and without fluid accumulation. Laboratory data did not show remarkable findings. She received excisional biopsy. The pathological report revealed panniculitis at that time. After the surgery, she still had erythema, swelling, and pain at the same site. She came to our Department of Plastic Surgery again. Physical examination noted a 4.5 x 2.0 cm mass with tenderness. Excisional biopsy was performed this time. Gross examination of the surgical specimen revealed a tan-to-white solid lesion. Microscopically, the lesion revealed areas of fibrinoid necrosis, mixed acute and chronic inflammation, and granulomatous reaction in the dermis and subcutis (Fig. 1). Parasitic larvae were seen focally (Fig. 2A, B). The larvae consisted of external noncellular eosinophilic tegument, as well as internal pale myxoid matrix with longitudinal smooth muscle fibres (Fig. 3A). Specific ovoid bodies with concentric calcified lamellae, termed calcareous corpuscles, were noted (Fig. 3B). The histopathological features were consistent with the diagnosis of human subcutaneous sparganosis. Tracing back to the contact history, she admitted using flesh from an unknown animal as a poultice applied to a wound. She also ate raw fish and undercooked beef.

Discussion

Sparganosis is a...


View full text...