Lobomycosis and squamous cell carcinoma.

The occurence of squamous cell carcinoma on long-lasting ulcers is classic. Malignant transformation may occur on burn scars and chronic ulcers of varying etiology, including infectious agents. Transformation of old lobomycosis lesion scars into squamous cell carcinoma has been rarely reported. Careful and long-term follow-up of such patients is important to avoid carcinomatous transformation.

A 87-year-old man presented a 30-year history of disseminated cutaneous lesions. He also noted that a lesion on the lower right limb had ulcerated during the past seven months. He had worked as a rubber worker in the Purus river banks, Amazon region for many years.

Physical examination revealed multiple illdefined, shiny nodules on the abdomen, right elbow and left lower limb (Figure 1). A vegetant and ulcerated lesion was also seen on the lateral aspect of the lower third of the left calf (Figure 2). There were no palpable lymph nodes.

FIGURE 1

Multiple ill-defined, smooth, shiny, elastic nodules on the left lower limb

FIGURE 2

A vegetant and ulcerated lesion on the lateral aspect of the lower third of the left calf

Histopathological examination of the ulcerated lesion revealed epithelial tumor islands of varying size in the dermis. Horn pearls and dyskeratotic cells with hyperchromatic nuclei were present within the islands. (Figure 3). GMS stain showed the typical yeasts of lobomycosis within the tumoral tissue (Figure 4). Based on clinical and histopathological findings, a diagnosis of squamous cell carcinoma in association to lobomycosis was given. Cranial, chest and abdominal computer scans and inguinal ultra-sound disclosed no abnormalities. The tumoral lesion was excised but the patient was lost to follow-up.

FIGURE 3

Histopathological examination revealed epithelial tumor islands of varying size in the dermis. Horn pearls and dyskeratotic cells with hyperchromatic nuclei are present within the islands (HE X 20)

FIGURE 4

GMS stain showed the typical yeasts of lobomycosis in chains of uniform round to oval cells within the tumoral tissue

Since Marjolin's initial description of an indolent ulcer arising on a burn scar,[1] malignant transformation of not only burn scars but chronic ulcers secondary to trauma, pressure, amputation, chronic lymphedema, chronic pilonidal sinuses, chronic sinuses, hidradenitis suppurativa, and infectious diseases such as leprosy and tuberculosis have been described.[2-4] Transformation of old lobomycosis lesion scars into squamous cell carcinoma is rare but has been previously reported in Central Brazil.[5,6]