Eumycotic mycetoma in the leg with a bone cyst in fibula

P VS Prasad¹ , Raj V George² , Elizabeth K Paul³ , S Ambujam¹ , S Sethurajan¹ , B Krishanasamy¹ , LL Rao¹

¹ Department of Dermatology, Rajah Muthaih Medical College & Hospital Annamalai University, Annamalai Nagar- 608 002, India
² Department of Radiology, Rajah Muthaih Medical College & Hospital Annamalai University, Annamalai Nagar- 608 002, India
³ Department of Pathology, Rajah Muthaih Medical College & Hospital Annamalai University, Annamalai Nagar- 608 002, India

Correspondence Address:
P VS Prasad
Department of Dermatology, Rajah Muthaih Medical College & Hospital Annamalai University, Annamalai Nagar- 608 002
India

Introduction

Mycetoma is a chronic disease of the skin, subctaneous tissue and bones characteristically affecting the foot. It can also affect other parts of the body.[1] The infection is caused by either a bacterium that is actinomycetes or by higher fungi (eumycetoma agent).

In India mycetoma is commonly caused by the species Madurella mycetomatis.[2] The disease was first recognised by Dr. Gill in 1842 from South India.[3] It is largely confined to tropical and subtropical areas. It is mainly seen in Africa, India, Mexico and parts of South America.[4] The disease presents first as painless papules and nodules and then progresses to form pustules which break down to form sinuses and open onto the skin surface discharging purulent or seropurulent materials with various colours of granules like yellow, black, red or white. It may progress to erode the cortex of the bone and produce cystic defects in the medulla.[2] Treatment with antifungals is not encouraging and beneficial only in some patients of eumycotic mycefoma. Wide excision has been tried in some, failing which amputation remains the only effective treatment.[1]

Case Report

A 61 - year-old man, a farmer presented with a history of swelling of the right leg of 8 years duration with multiple discharging sinuses. He had a history of thorn prick one year prior to the onset of the lesion. On examination a large swelling measuring 14 x 10 cm in size extending from the right knee joint to the shin was seen [Figure - 1]. It was firm in consistency. Multiple sinuses were seen with some of them discharging black granules. KOH examination from the granules revealed hyphae. Histopathological examination of the lesion was consistent with eumycatic mycetoma. Radiological examination of the right leg revealed osteolytic lesion in the fibula with a bone cyst [Figure - 2]. The patient was treated with fluconazole 150 mg per week and is under observation.

Discussion

The major criteria for clinical diagnosis of mycetoma are (1) swelling (2) sinuses and (3) granules. It shows typical clinical features which makes the diagnosis easier. The site commonly involved is the foot but involvement of other sites are also recorded. Black granules are characteristic of eumycotic mycetoma. Our patient showed the characteristic lesion with black granules. The diagnosis in our patient was supported by KOH examination and confirmed by histopathological examination. From the granules Madurella mycetomatis was isolated in the culture.

Bone involvement is known to occur in eumycotic mycetoma. The changes comprise of cyst - like cavities in the metatarsal bones and bone sclerosis.[4] These changes are recorded mainly in the foot. Our patient had a bone cyst with osteolytic lesion in the fibula. The changes in the long bones in association with mycetoma is an unknown entity.

As surgery could not be contemplated in our patient he was treated with oral fluconazole. The actual response could not be assessed as the patient was lost to follow up.

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