Pyoderma gangrenosum: An uncommon cause of nonsexually acquired genital ulcer disease.

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis affecting various sites, isolated genital PG being an uncommon presentation. We report a case of a 50-year-old diabetic male who presented with 2 penile ulcers. Extensive evaluation was done for sexually and nonsexually transmitted infections, malignancy, drug-induced vasculitis, and immunobullous etiology. A diagnosis of PG was made based on the clinical findings and histopathological exclusion of other causes. The patient showed a rapid response to prednisolone, dapsone, and colchicine. This report highlights the importance of keeping PG as a differential diagnosis in cases of genital ulcers which may mimic other sexually transmitted infections. Copyright:

Introduction

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis (incidence: 0.73/1,00,000 person years) affecting various sites, isolated genital PG being an uncommon presentation. Almost 75% cases are associated with underlying systemic diseases such as inflammatory bowel disease, arthritis, and hematological disorders.[1] We hereby report a case of isolated penile PG without systemic involvement.

Case Report

A 50-year-old gentlemanpresented with 2 ulcers over the glans penis for 10 days. They started as minimally painful papules which rapidly ulcerated with increase in size. There was no history of discharge, bleeding, fluid-filled lesions, trauma, recurrent oral ulcers, redness of eyes, joint pains, gastrointestinal symptoms, urethral discharge, fever, loss of weight, or appetite. The patient was married and gave a history of multiple extramarital contacts with commercial sex workers, last contact being 15 days before the onset of the ulcers. There was no history of sexually transmitted disease (STD) in partner. He was a known diabetic on irregular treatment for 5 years.

General examination was unremarkable. Peripheral pulses were palpable. There was no lymphadenopathy. Glans penis had two well-defined tender, indurated ulcers with necrotic grayish-white slough, regular margins, undermined edges, erythematous border- measuring 3 cm × 2 cm and 0.5 cm × 0.5 cm [Figure 1a]. They did not bleed on touch. Rest of the mucosa, skin, palms, soles were normal.

Figure 1

(a) Two ulcers with necrotic slough over the glans penis. (b) Photomicrograph of first biopsy showing acute inflammatory infiltrate and fibrinoid necrosis of vessels (×40). (c) Photomicrograph of repeat biopsy showing mixed inflammatory cell infiltrate (×40). (d) Healing ulcers showing healthy granulation tissue after treatment with immunomodulators

Laboratory investigations

Gram's stain revealed multiple polymorphonuclear leukocytes, no organisms. Tzanck smear showed no multinucleated giant cells or acantholytic cells. Screening for HIV, Hepatitis B and C, syphilis (VDRL and TPHA), and herpes simplex virus serology were nonreactive. His fasting, postprandial sugars, and HbA1c were elevated (314 mg/dl, 362 mg/dl, and 7.3%, respectively). Pus culture for Haemophilus ducreyi was sterile. The Mantoux test was positive (15 mm × 17 mm). Skin biopsy [Figure 1b] showed acanthosis, fibrinoid necrosis in vessels, acute inflammatory cell infiltrate, and granulation tissue in the dermis along with necrotic debris. There was no evidence of dysplasia or malignancy. Repeat biopsy showed large areas of ulceration. Dermis showed granulation tissue with dense mixed inflammatory infiltrate of neutrophils, lymphocytes, and occasional plasma cells; there is no evidence of vasculitis, epithelioid cell granuloma, Crohn's disease, or malignancy [Figure 1c].

Ziehl–Neelsen staining did not show acid-fast bacilli, and culture for typical, atypical mycobacteria and tissue CBNAAT were negative. Chest X-ray was normal and contrast-enhanced computed tomography abdomen showed 16 mm × 10 mm right inguinal lymph node; no other significant abnormality. Pathergy test, stool for occult blood, and ANA were negative. Serum protein electrophoresis was normal.

With the initial acute presentation and history of high risk behavior, considering a differential diagnosis of primary chancre with mixed anerobic infection, chancroid, or herpes genitalis, we empirically treated him with local cleansing and oral antibiotics (metronidazole and ciprofloxacin). Metformin and teneligliptin were started. After ruling out STD, we considered differentials of noduloulcerative genital tuberculosis, atypical mycobacterial ulcer, malignancy, and PG. We diagnosed PG based on clinical findings and exclusion of other causes. We started him on dapsone 100 mg once daily and colchicine 0.5 mg thrice daily. After an initial response, the patient discontinued treatment by himself and developed another ulcer near the meatal opening. He was restarted on dapsone and colchicine. Prednisolone was added for 6 weeks with a maximum of 40 mg daily with which he showed rapid improvement [Figure 1d].

Discussion

PG is an uncommon neutrophilic disease, pathophysiology of which is incompletely understood. It involves a complex interplay of genetic influence, dysregulation in innate immunity, and neutrophil dysfunction.[23] It can affect all age groups with no sex predilection.[3] Clinical variants include classic ulcerative, bullous, pustular, vegetative, peristomal, etc. Various diagnostic criteria have been proposed although validated criteria are still lacking.[3] PG is an uncommon disease affecting all age groups. Diagnosis is made by excluding other causes. Pathergy may be seen in 20%–30% patients.[2] Management includes avoidance of triggers, local wound care, and immunomodulatory therapies.[3]

Few cases of isolated genital PG have been reported with only 4 from India.[4567] Our patient responded well to a combination of therapy with dapsone, colchicine, and oral prednisolone in addition to local wound care. This case is presented to highlight the importance of keeping PG as a differential diagnosis of penile ulcers refractory to usual treatment modalities.

Declaration of patient consent

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Nil.

Conflicts of interest

There are no conflicts of interest.