Rhinosporidiosis is an enigmatic entity and poses a major health problem in the developing countries of South‑East Asia. A soft friable polypoid nasal mass is the most common presentation, while sparse literature is available on extranasal involvement. We describe the case of a 35‑year‑old female patient who presented with a slow‑growing soft‑tissue swelling with ulceration over the thigh. On clinical and radiological examination, a provisional diagnosis of soft‑tissue neoplasm was made. After resection, histopathological sections showed a closely packed cyst with innumerable endospores. The present case report documents the rare occurrence of an incidentally detected cutaneous rhinosporidiosis causing diagnostic difficulty.
Rhinosporidiosis, a rare granulomatous entity, is known to be hyperendemic in the southern part of India and Sri Lanka. This lesion caused by Rhinosporidium Seeberi,
taxonomically under Mesomycetozoa, commonly affects the mucosal membrane of the nasal cavity and nasopharynx. Males are commonly affected. Only a handful of case reports have described cutaneous and soft‑tissue involvement.[3‑5] The mainstay of treatment is excision, but the disease has a tendency to recur posing a challenge. Here, we describe a rare case of cutaneous rhinosporidiosis in an immunocompetent female misdiagnosed initially as a soft‑tissue neoplasm.
A 35‑year‑old female of low socioeconomic status from rural India presented in the surgery outpatient department with a solitary large soft‑tissue lesion over the outer aspect of the right thigh for 6 months. The lesion progressively increased in size over the last 3 months. Central ulceration was noted. There was no history of any underlying systemic illness, transplantation or use of immunosuppressive drugs. Her fasting blood sugar was 90 g/dl. Aclinical diagnosis of soft‑tissue neoplasm was made. FNAC from the nodule in the thigh region was done. It was suggestive of an inflammatory lesion. Aspiration cytology
showed the presence of plenty basophilic endospores
morphologically resembling Rhinosporidium [Figure 1a].Consequently, it was surgically excised. Gross examination revealed a single soft‑tissue mass measuring 7 cm × 7 cm × 4 cm. Central ulceration was identified measuring 3 cm × 3 cm × 3 cm [Figure 1b]. Representative sections were taken and sent for further processing.
Histopathological examination of the haematoxylin and eosin (H and E)‑ and periodic acid–Schiff (PAS)‑stained sections from nodular lesion of the thigh showed hyperplastic stratified
squamous epithelium with many well‑defined thick‑walled sporangia in the underlying dermis and subcutaneous area. The sporangia were in different stages of development and showed many endospores inside [Figure 1c and d]. Final diagnosis of cutaneous rhinosporidiosis was made.
During review of the case, the patient informed that she had a nasal bleed 2 years ago and was operated for some lesion. She had lost all documents, but she was prescribed 100 mg of daily dapsone which she stopped mid‑course. On further investigation, multiple subcutaneous nodules of
small‑to‑medium size were detected over the neck, anterior chest, arm and gluteal region. All lesions were removed, and after histopathological examination, final diagnosis was revised from solitary cutaneous to disseminated cutaneous rhinosporidiosis. On enquiry, the patient reported to have a history of pond bathing. The patient was referred to the department of otorhinolaryngology for repeat nasal and nasopharyngeal examination. She was administered dapsone 100 mg/day for 6 months. No mucosal lesions were noted. X‑ray chest was also within normal limits. The patient is doing fine on 1‑year follow‑up and has not reported any new lesions any where in the body.
Rhinosporidiosis is a chronic granulomatous disease that mostly affects nasal, nasopharyngeal and conjunctival mucosa. It has been rarely reported in areas such as brain, bone, liver, lung, spleen, anal canal and genitourinary tract. The disease is mainly prevalent in hot tropical climates like India and Sri Lanka, though few cases have been reported in developed countries like the USA and Europe.
In our case, the female from low socioeconomic status initially presented only with a solitary lesion over the inner aspect of the thigh. There was no documented lesion anywhere else at that time. Considering the consistency and rapidly enlarging mass, an initial diagnosis of a soft‑tissue neoplasm was made. It was after aspiration cytology and histology that a final diagnosis of rhinosporidiosis was made. PAS stain on biopsy samples also complemented the light microscopic diagnosis.None of the previous cases reported rhinosporidiosis initially mimicking soft‑tissue neoplasm located solely in the thigh.[9‑12]
In addition, as elaborated in Table 1, warty lesion, nodule or ulceroproliferative lesions were the initial presentation in other literatures. Aravindan et al. reported a case of enlarging scapular mass in an elderly male misdiagnosed clinically and radiologically as chondrosarcoma. On histological examination of the excised tumour, the lesion was found to be a case of rhinosporidiosis. There was a past history of excision of nasal polyp 20 years ago. Avadhani et al. reported another case of cutaneous rhinosporidiosis from India which presented as a progressive vascular soft‑tissue mass on the leg and was provisionally diagnosed as a soft‑tissue sarcoma. In the present case, the middle‑aged woman presented with large soft‑tissue lesions over the thigh. The clinical diagnosis of soft‑tissue tumour was made. After histopathological
confirmation using H and E as well as PAS stain, the case was treated as cutaneous rhinosporidiosis.
Treatment of the disease on accessible sites is complete excision with or without the help of electrocautery. The treatment of disseminated and recurrent cases is very challenging. Failure of drug therapy may also occur due to impermeability of the sporangial wall. Hence, awareness of the varied presentations and critical appraisal of cytology and histological findings are essential for early identification and management of rhinosporidiosis, especially in countries where the disease is endemic.
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Conflicts of interest
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Kavita Jain, S. M. Sarfaraj, Moumita Sengupta, Chhanda Datta, Uttara Chatterjee
Department of Pathology, IPGMER and SSKM Hospital, Kolkata, West Bengal, India