Granulomatous pyoderma gangrenosum of the genitalia in the absence of Crohn's disease.

Pyoderma gangrenosum (PG) is a rare ulcerative neutrophilic disorder of the skin. Atypical variants of PG such as vegetative PG, bullous PG, and pustular forms are described in literature. Occasionally, granulomatous reaction in dermis may be seen on histology when PG is associated with Crohn's disease or in the vegetative variant of PG. We report a case of granulomatous PG involving the genitalia in a 43-year-old female without associated inflammatory bowel disease.

INTRODUCTION

Pyoderma gangrenosum (PG) is a rare ulcerative skin disease of unknown etiology, characterized by neutrophilic infiltration in the dermis. It is, usually, associated with systemic diseases in about 50% of the patients. Apart from the classical ulcerative type, other variants are bullous, pustular, and vegetative PG. Granulomatous changes are seen in histopathology in the vegetative type of PG or when PG is associated with Crohn's disease.[1] We report a rare case of PG of the genitalia in a female with granulomatous histopathology.

CASE REPORT

A 43-year-old female presented with a painful solitary ulcer on the genitalia of 1-year duration. The lesion started as a pustule which ruptured and formed the ulcer. There was no history of fever, joint pain, oral ulcers, abdominal pain, loose stool, preceding trauma, or weight loss. Her general physical and systemic examination was normal. Cutaneous examination revealed a single ulcer of 3 cm × 4 cm size with hyperpigmented irregular margins and slightly undermined edges located on the lower part of mons pubis extending to the upper part of vulva [Figure 1]. The ulcer was slightly tender, nonindurated, and floor was covered with red granulation. There was no regional lymphadenopathy. The differential diagnoses considered were PG, tuberculous ulcer, deep fungal infection, donovanosis, and Crohn's disease. Findings of routine blood workup, peripheral smear, urine analysis, stool examination, chest X-ray and colonoscopy were normal. Mantoux test, antineutrophil cytoplasmic antibody, HIV testing, and Venereal Disease Research Laboratory were negative. Tissue smear for Donovan bodies was negative. At the site of venepuncture, patient developed an indurated plaque of 1 cm × 2 cm which was suggestive of pathergy phenomenon [Figure 2]. Gram-stain and culture and sensitivity done from the floor of the ulcer showed gram negative bacilli sensitive to gentamicin. Smear for acid-fast bacilli (AFB) done from the floor of the ulcer was negative. Histopathology showed infiltration of neutrophils, lymphocytes, and plasma cells in the dermis with occasional ill-defined granulomas and giant cells. Special stains for AFB and fungus were negative [Figure 3a and b]. Patient was given gentamicin for 3 weeks without much improvement. Based on clinical and histopathological features, a final diagnosis of the granulomatous variant of PG was made, and patient was given prednisolone 30 mg/day. At 1 month follow-up, ulcer had completely healed with mild scarring [Figure 4]. Treatment was stopped after 1 month, and there was no recurrence.

Figure 1

A single ulcer of 3 cm × 4 cm size with hyperpigmented irregular margins and slightly undermined nonindurated edges on the mons pubis extending to the upper part of vulva

Figure 2

Indurated plaque of 1 cm × 2 cm at the site of venepuncture suggestive of pathergy phenomenon

Figure 3

(a and b) Dense inflammatory infiltrate in dermis consisting of neutrophils, lymphocytes, plasma cells, and giant cells

Figure 4

Healed ulcer at 1 month follow-up

DISCUSSION

Pyoderma gangrenosum is an uncommon inflammatory disorder of the skin characterized by painful ulcers with undermined violaceous borders and histopathological finding of dense neutrophilic infiltration in the dermis referred to as “sea of neutrophils.” PG may be associated with inflammatory bowel disease, arthritis, haematological diseases or drugs (gefitinib, propylthiouracil, isotretinoin, pegfilgrastim) in up to 50% of cases.[1] PG is, usually, seen over the trunk and lower extremities, but solitary lesion over the genitalia is uncommon.[23] PG lesions on histopathology may show granulomatous foci when it is associated with inflammatory bowel disease, especially Crohn's disease.[4] Other uncommon variants of PG are pustular PG, bullous PG, and vegetative PG.

Vegetative PG or superficial granulomatous pyoderma is a localized indolent variant of PG described by Wilson-Jones and Winkelmann in 1988.[5] It presents as a slowly enlarging relatively painless ulcer with exophytic or vegetating clean granulation. Histopathology reveals neutrophilic abscesses, chronic inflammatory infiltrate of giant cells, plasma cells and eosinophils, palisading granulomatous reaction, and sinus formation.[67] Cutaneous tuberculosis and metastatic Crohn's disease may present with genital ulcers with granulomatous histology and needs to be ruled out.[8] Pathergy phenomenon which refers to localization of PG lesions at site of trauma is rare in the vegetative type. Vegetative PG is, usually, not associated with systemic diseases, unlike classical PG and often responds well to mild treatment options like topical or intralesional steroid and antibiotics like minocycline and sulfonamides. Other treatment options are systemic corticosteroids, dapsone, clofazimine, thalidomide, topical sodium cromoglycate, and cyclosporine.[6910]

This case is reported to highlight the fact that PG should be considered as a differential diagnosis for genital ulcer and though usually histopathology of PG shows dense dermal neutrophilia, rarely granulomatous reaction may be seen.