Pyoderma Gangrenosum Secondary to Severe Congenital Neutropenia.

We encountered a case of a man who was diagnosed with severe congenital neutropenia as a child and presented at the age of 45 years with pyoderma gangrenosum (PG) of the lower leg. PG associates with an underlying systemic disease, most commonly inflammatory bowel, rheumatic, or hematological disease or malignancy. However, in many cases, the underlying disease was not known. Surgery can trigger PG. The histopathological features of PG were nonspecific, and diagnosis requires excluding other conditions that have a similar appearance. Our analyses showed that the PG in our case was secondary to severe congenital neutropenia, which had promoted an infection of keratinous cysts. The patient bore a mutation in the ELANE gene encoding neutrophil elastase. Only 1 other case of neutropenia-associated PG has been reported previously: the association was only suspected. The present complex case was effectively treated by systemic treatment of the neutropenia with granulocyte colony-stimulating factor and regional surgical treatment. Histology of the excised tissue revealed keratinous cysts that were diffusely distributed with inflammatory granulation tissue. We believe that the rupture of the walls of the keratinous cysts may have caused the PG. At the time of writing (3 years since the initial presentation), the PG has not recurred. This case shows the importance of performing detailed examinations, including blood tests, to determine the disease underlying PG. This was because if the underlying disease was identified, its treatment was likely to promote healing of the wound after local surgery and prevent recurrence.

Reassessment of histopathology and dermoscopy findings in 145 Japanese cases of melanocytic nevus of the sole: toward a pathological diagnosis of early-stage malignant melanoma in situ.

Recently, dermoscopic visualization has been improved, allowing for the identification of malignant melanoma (MM) of the sole in situ. When the parallel ridge pattern is evident on dermoscopy, the proliferation of solitarily arranged melanocytes in the crista profunda intermedia should be examined histologically, since this may be a clue to the early diagnosis of MM in situ. We reviewed 145 Japanese cases of melanocytic nevus on the sole, and investigated several useful histological features for the diagnosis of MM in situ using a recent proposal as well as several standard histological criteria of MM in situ. Five cases were considered to be an early-stage MM in situ out of 145 cases previously diagnosed as melanocytic nevi of the sole. These cases showed several specific features, including solitarily arranged melanocytes or melanocyte nests comprising fewer than four cells. Our findings indicate that early-stage MM of the sole in situ can be diagnosed by using new dermoscopy-related histological findings. They are (i) irregular distribution of solitary melanocytes at the crista profunda intermedia with or without small nests (up to three melanocytes) on the slope of rete ridges; and (ii) larger melanocytes with a halo around the nucleus.