Pseudoxanthomatous lesions with membranocystic changes of collagen fibers in an SLE patient receiving long-term steroid treatment

Pseudomembranous changes in the dermis: A novel observation and potential clue for evolving lipodermatosclerosis?

Lipodermatosclerosis (LDS) is a well-recognized form of fibrosing panniculitis. Although chronic cases are readily diagnosed, early and evolving lesions may be clinically mistaken for cellulitis and other forms of panniculitis. Most pathologists are familiar with a pseudomembranous type of fat necrosis as a useful feature of chronic LDS. Although nonspecific, this distinctive pattern of fat necrosis helps in supporting a diagnosis of LDS in the appropriate clinical context. The histopathologic features of early and evolving LDS and those involving the dermis are less well documented. We report a case of early LDS showing extensive pseudomembranous changes in the dermis on a superficial skin biopsy where progression to a classic established lesion was documented clinically. We suspect that this previously unreported and unusual finding may be a histopathologic clue for evolving lesions of LDS.

Angiokeratomas in juvenile dermatomyositis

Juvenile dermatomyositis (JDM) is an uncommon disease that features muscle weakness, a characteristic rash, and vascular changes in skin, muscle, and other organs. We report a patient with JDM who developed multiple angiokeratomas, one of which was calcified. Electron microscopy of an angiokeratoma revealed altered connective tissue consistent with abnormal collagen. To our knowledge, angiokeratomas occurring in association with JDM have not been previously reported. Abnormal collagen distinguishes the angiokeratomas in our patient from those seen in other conditions. We propose that the angiokeratomas resulted from a progressive compensatory response to the obliterative angiopathy of JDM.