Projects

A five-year girl was referred to our centre with swelling over the right lower back. The child was evaluated to rule out chronic cutaneous tuberculosis, lymphoma and soft tissue tumor. Biopsy of the lesion on culture yielded Basidiobolus species. Whole genome sequencing of the isolate identified it as Basidiobolus meristosporus. Sequencing of fungi pathogenic to humans which cannot be differentiated by conventional methods of speciation becomes essential to assign pathogenicity, understand epidemiology and resolve the nuances in the ever-evolving taxonomical classification.

Keywords: Entomophthoromycosis, Basidiobolus, Mimic, Biopsy, Molecular diagnosis

1. Introduction Subcutaneous entomophthoromycosis are rare infections involving skin and subcutaneous tissues in immunocompetent hosts. These are caused by saprophytic fungi of Genera Basidiobolus and Conidiobolus. Basidiobolus is a ubiquitous fungus, residing in tropical and sub-tropical marshes [1]. Most human infections are caused by B. ranarum and are reported from tropical regions. It commonly affects children and presents as typically painless indurated swellings with secondary skin changes, usually on the limbs and trunks mimicking chronic granulomatous diseases like tuberculosis or even malignancy [2]. Timely definitive diagnosis by culture and biopsy is imperative to avoid unwarranted surgery and deliver the right treatment.

In the recent past, there have been reports of Basidiobolus meristosporus being implicated in human infections [3]. Even though there is currently no difference in the management strategies for different species, sequencing data will add to the existing knowledge of the pathogenic species and understand epidemiology. This prompted us to identify the isolate by sequencing.

Here we present a case of an immunocompetent five-year-old girl with a soft tissue swelling on the right upper buttock caused by Basidiobolus meristosporus  2. Case

A five-year old girl presented with a history of swelling over the right lower back for three months. Initially the swelling was peanut sized and progressively increased over three months to occupy the entire right upper buttock. She had mild itching and scaling over the lesion with significant weight loss. Patient sought treatment at a local clinic where it was diagnosed to be an abscess and a drainage was attempted but abandoned due to a bloody aspirate. Another similar lesion was noted on the back of right thigh two weeks(day −14) before the current presentation. She was evaluated at our facility by the teams from Paediatrics, Paediatric surgery and Paediatric haemat-oncology and was admitted to the hospital for further work-up (day 0).

On examination, she was febrile with generalized lymphadenopathy (cervical, axillary and inguinal). A 10 × 8cm firm, indurated, fixed scaly painless lesion was noted in right lower back just above the iliac crest with a scar of attempted drainage. The surface was erythematous without any rise in local temperature. Postero-medial aspect of right upper thigh had another 3 × 3cm synchronous lesion (Fig. 1). Hemogram showed leukocytosis with mild eosinophilia and elevated erythrocyte sedimentation rate (ESR). Radiographs of right hip and femur showed soft tissue shadow over the affected area without calcification/periosteal involvement (Fig. 2). Soft tissue ultrasonography revealed subcutaneous irregular cystic lesion in right lumbar region with overlying subcutaneous and intramuscular edema, increased peri-lesional vascularity with no calcification (Fig. 3). A contrast enhanced computed tomography (CT) showed ill-defined peripherally non-homogenously enhancing hypodense areas with few cystic areas in subcutaneous plane of right lumbar region and in right upper posteromedial thigh with inguinal and obturator lymphadenopathy