Pyoderma gangrenosum with its subtype affecting oral mucosa pyostomatitis vegetans following skin melanoma surgical excision in a patient with ulcerative colitis: a case report

Pyoderma gangrenosum (PG) is a disease which aetiology has been described only partially. In the course of the disease damage to blood vessels occurs secondarily to neutrophils infiltration into the affected site. Skin lesions may be located throughout the body, but lower limbs are predominantly affected. The primary lesions include papule, nodule, pustule, vesicle which transform into peripherally growing skin ulcerations. Pyoderma gangrenosum may coexist with multiple conditions including haematologic disorders, inflammatory bowel disease, rheumatoid arthritis and other autoimmune diseases and malignancies [1–3].
Pyostomatitis vegetans (PSV) is classified by many authors as a subtype of PG, which affects oral mucosa. The majority of PSV cases coincide with inflammatory bowel disease [4].
This paper describes a case of a 69-year-old patient, with a history of ulcerative colitis (UC). Due to UC, the patient participated in a clinical trial of a biologic drug in 2009–2010, but no detailed data on the treatment were available. The disease was complicated with several episodes of gastrointestinal bleeding. The last reported bleeding occurred 3 months before the admission to the Clinic of Dermatology. It resulted in hypovolemic shock and it was associated with the occurrence of mucosal lesions. The patient was admitted to the Clinic of Dermatology in Bydgoszcz because of minor oral mucosa erosions observed for 3 months preceding hospitalization. During physical examination a pigmentary lesion sized 40 × 30 mm on the patient’s back was observed. Clinical and dermoscopic characteristics of the lesion were typical of melanoma. Histopathological examination of the excised lesion confirmed melanoma pT1a (0.5 mm in Breslow scale) and complete excision. Clinical and dermoscopic presentation of melanoma diagnosed in our patient is presented in Figure 1.
Shortly after the skin lesion had been excised, a rapidly spreading ulceration on the patient’s right lower limb appeared. The ulceration was 8 cm in diameter, with a necrotic crust in the middle of the lesion and an elevated dark red edge. Moreover, single pustules, which initially appeared on the patient’s face, trunk and limbs began to transform into minor ulcerations. Erosions of oral mucosa progressed to deep ulcerations with inflammation in adjacent areas. Additionally, mucosal pustules within the oral cavity could be observed. Pathergy reaction within the post-surgical wound was present. Skin...


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