Case 3. Superficial granulomatous pyoderma

Pyoderma granulomateux superficiel

INTRODUCTION

Superficial granulomatous pyoderma is a rare variant of pyoderma gangrenosum, which is often diagnosed at a late stage because of misleading clinical-histopathological features. We report a new case of this rare disease.

CASE REPORT

A 67 year-old man presented with inflammatory lesions that had become ulcerated over the past 4 months despite prolonged antibiotic therapy. The histopathological aspect was initially suggestive of palisading granuloma annulare and subsequently a necrotizing granuloma compatible with a mycobacteriosis. The various supplementary examinations eliminated the possibility of an infectious or systemic disease. The lesions became painful and ulcerated. A second biopsy showed a neutrophilic dermatosis with dermal necrosis and a granuloma leading to the diagnosis of superficial granulomatous pyoderma. The lesions healed after 3 months of systemic corticosteroids at the dose of 1 mg/kg/day.

DISCUSSION

The clinical features of superficial granulomatous pyoderma are similar to those of classical pyoderma gangrenosum. However, its histological profile is more superficial and is associated with dermal granulomas. The latter are unusual in neutrophilic dermatosis and would suggest an infectious disease. This explains the frequent diagnostic errors, with inappropriate anti-infectious treatments and notably unnecessary surgical exeresis.

Superficial granulomatous pyoderma: a case report of two Japanese patients and clinical comparison with foreign patients

Superficial granulomatous pyoderma (SGP) is an unusual variant type of pyoderma gangrenosum characterized by a benign course and specific histological features; it is quite a rare cutaneous disorder in Japan. We reported two Japanese cases of SGP and compared the clinical features of 13 Japanese cases with those of 42 foreign cases. Case 1 was a 53-year-old female who presented with three indolent and ulcerative plaques with elevated edges on the back and the posterior portion of the left thigh. Case 2 was a 74-year-old female who presented with crusted and vegetative erythematous plaques on the left shoulder and left upper arm. Histological examinations revealed a characteristic three-layer granuloma in each case. Laboratory and physical examinations found no abnormalities. Topical corticosteroid, oral administration of minocycline, and/or additional supplementation with corticosteroid were effective. In comparison with foreign cases, Japanese cases show a possible differentiation in the ratio of sex and distribution of the ulcer. Females have a high incidence and the extremities are frequently involved area in Japanese cases. Up to now, 11 cases of SGP have been reported in Japan. To our best knowledge, our patients are the first Japanese cases described in the English literature.