Elsevier Global Medical News. 2011 Aug 4, B Jancin
The skin may hold the key to differentiating classic pemphigus from the heterogenous autoimmune syndrome known as paraneoplastic autoimmune multiorgan syndrome.
It is a distinction of critical prognostic importance, because paraneoplastic autoimmune multiorgan syndrome (PAMS) typically is rapidly fatal, according to Dr. Sergei A. Grando, professor of dermatology and biologic chemistry at the University of California, Irvine. “The vast majority of patients die within several months of diagnosis, usually due to infections or respiratory failure, often taking the form of multiorgan system failure.”
Two-thirds of patients with PAMS have a known internal malignancy at the time of their first mucocutaneous eruption. The most common of these neoplasms are non-Hodgkin’s lymphoma, which is present in more than 40% of PAMS patients; chronic lymphocytic leukemia, present in 30%; Castleman disease, present in 10%; and thymoma, present in 6%.
When a patient meets the diagnostic criteria for PAMS without having a known cancer, it is appropriate to launch a search for hidden malignancy, said Dr. Grando.
A key distinction between the skin lesions of PAMS and classic pemphigus is that PAMS involves inflammatory macules, papules, plaques, and blisters occurring on an inflammatory background over the trunk and extremities, including the palms and soles, but sparing the scalp.
In contrast, the generally more vesicular blisters and crusted erosions of pemphigus vulgaris display little erythema and usually occur on a noninflammatory background on the scalp, trunk, and extremities (but sparing the palms and soles). The most common location for skin lesions in PAMS is the palms; in pemphigus vulgaris, it is the scalp.
Also, Nikolsky’s sign is positive in pemphigus vulgaris, but negative in PAMS, added Dr. Grando, who was among the investigators who first described PAMS a decade ago (Arch. Dermatol. 2001;137:193-206).
PAMS is characterized by severe and diffuse oral mucous membrane involvement, with persistent painful stomatitis because of blisters and erosions, and frequent involvement of other mucous membranes, including the eyes and genitalia. Cicatrizing conjunctivitis is particularly common in PAMS. In contrast, oral mucous membrane involvement in pemphigus is more discrete, with the eyes or other nonoral mucosa rarely involved.