Dermatomyositis is an autoimmune disease that has a characteristic skin eruptionand may be autoimmune; it is sometimes associated with malignancy. Because this is a rare disease, not much is known about this association and there are no guidelines to my knowledge, but experts often recommend CT scanning to exclude coexistent malignancy. In one retropsectove review, malignancy ocurred in 16 of 4o patients.
Agnès Sparsa, Eric Liozon, François Herrmann, Kim Ly, Valérie Lebrun, Pascale Soria, Véronique Loustaud-Ratti, Marie-Laure Bouyssou-Gauthier, Serge Boulinguez, Christophe Bédane, Marie-Odile Jauberteau, Elisabeth Vidal, and Jean-Marie Bonnetblanc
Routine vs Extensive Malignancy Search for Adult Dermatomyositis and Polymyositis: A Study of 40 Patients
Arch Dermatol, Jul 2002; 138: 885 – 890.
Scheinfeld N. A review of the cutaneous paraneoplastic associations and metastatic presentations of ovarian carcinoma. Clin Exp Dermatol.2008 Jan;33(1):10-5. Epub 2007 Nov 3. (s)