A Case Report of Necrotizing Neutrophilic Dermatosis: A Sheep in Wolf's Clothing

Abstract

Neutrophilic dermatosis (ND) is a category of diseases characterized by trauma-induced, autoinflammatory cutaneous eruption. Comorbid systemic disease is common with a predilection for malignancy, inflammatory bowel disease, and rheumatologic disease. Rarely, it can manifest with aseptic shock, an entity referred to as necrotizing neutrophilic dermatosis (NND). NND may occur in the postoperative setting and is often misdiagnosed as a necrotizing soft tissue infection. Unfortunately, the treatment for a necrotizing soft tissue infection, namely, wide debridement, is often detrimental in the setting of NND. We present the case of a woman with underlying myelodysplastic syndrome who developed episodic postoperative hemodynamic collapse followed by delayed necrotic peristomal ulceration following colonic diversion for complicated diverticulitis. Infectious workup and operative re-exploration were unrevealing. Pathologic assessment of affected skin tissue showed changes consistent with ND, ultimately leading to the diagnosis of NND. Her clinical course dramatically improved with the initiation of immunosuppressive therapy. The mimicry of NND to a potentially lethal necrotizing soft-tissue infection creates a grave diagnostic dilemma in the postoperative period. A general lack of knowledge of NND among non-dermatologic specialists produces an opportunity for misdiagnosis and inappropriate surgical interventions, namely, serial debridement. Several clinical cues may aid in the earlier recognition of NND. The cornerstone of treatment involves systemic corticosteroid therapy with adjunctive therapy for refractory cases. NND must be considered in the differential diagnosis of necrotizing soft tissue infection as early recognition may result in the avoidance of deleterious surgical interventions.

Keywords: necrotizing neutrophilic dermatosis; necrotizing soft tissue infection; pathergy; pyoderma gangrenosum; surgery; sweet's syndrome.

Figure 1. Preoperative CT scan demonstrating thick-walled, mildly enhancing complex fluid collection anterior to the sigmoid colon consistent with a perisigmoid abscess of diverticular origin.

CT: computed tomography

Figure 2. (A) Postoperative day three, loop colostomy with venous congestion and contact bleeding but normal appearance of peristomal skin. Additionally pictured, tan-colored skin barrier ring and red rubber catheter stoma bar. (B) Postoperative day four, CT scan showing left upper quadrant loop colostomy with non-specific subcutaneous edema.

CT: computed tomography

Figure 3. (A) Interval improvement of perisigmoid fluid collection after fecal diversion. (B) Wall thickening with associated fat stranding of the ascending and proximal transverse colon concerning for colitis. (C) Persistent body wall edema without subcutaneous emphysema.

Figure 4. Pre-corticosteroid treatment imaging of cutaneous eruptions. (A) Peristomal region: confluent ulceration with central necrotic tissue overhanging demarcated violaceous border extending to and involving midline incision three days after re-exploration. (B) Laparoscopic port site: similar discoloration with central skin breakdown and characteristic satellite lesions at the port site.

Figure 5. Right lower quadrant punch biopsy with negative infectious stains. (A) H&E at 4× magnification, necrotic epidermis (arrows) with underlying mixed dermal inflammation consisting of a neutrophil-predominant infiltrate. (B) H&E at 20× magnification, mixed dermal infiltrate composed of neutrophils, lymphocytes, histiocytes (circle), and extravasated red blood cells (arrows).

H&E: hematoxylin and eosin

Figure 6. Post-corticosteroid treatment, day 28: dramatic improvement of cutaneous lesions showing border collapse, fading discoloration with central eschar, and skin dimpling/scarring. (A) Peristomal region. (B) Laparoscopic port site.