A 51-year-old woman with a history of asthma presented with 1 month of painful, red skin eruptions of the face and buttocks and the dorsal and palmar surfaces of both hands (Fig. 1). A skin biopsy from a lesion on the left elbow was nondiagnostic, showing dermal fibrosis and minimal inflammation. She was treated with topical clobetasol and oral fluconazole and valacyclovir, without improvement. Four weeks later, she noted joint pain and swelling in the hands, wrists, hips, and shoulders, as well as weakness of her upper legs. An echocardiogram was negative for endocarditis. Laboratory studies included hemoglobin of 12.5 g/dL (normal: 12.0–16 g/dL), hematocrit of 35.9% (normal: 36%–46%), erythrocyte sedimentation rate of 100 mm/h, C-reactive protein of 21.7 mg/L (normal: <8.0 mg/L), ferritin level of 1,177 ng/mL (normal: 10–200 ng/mL), aspartate aminotransaminase of 7 U/L (normal: 9–32 U/L), alanine aminotransferase of 87 U/L (normal: 7 - 30 U/L), aldolase of 10.9 U/L (normal: <7.7 U/L), angiotensin-converting enzyme of 59 U/L (normal: <53 U/L), and antinuclear antibody positive at 1:40 (speckled). Other tests were normal, including rheumatoid factor, anti-nuclear cytoplasmic antibody, immunoglobulin and complement levels, hepatitis markers, Lyme, and parvovirus. Electromyography of the right thigh showed active denervation in the right iliopsoas muscle without evidence of a peripheral neuropathy or myopathy. Treatment with 10 mg of prednisone lessened her joint pain, skin discontent, and proximal leg weakness.
Six weeks later, the patient reported intermittent vertical diplopia. Neuro-ophthalmic examination revealed visual acuities of 20/20 in each eye with an intact afferent visual system, including funduscopy. Pupils were equal in size and reacted normally. There was 2 mm of right ptosis. Ocular motility testing revealed limited supraduction and abduction of the right eye, and there was decreased sensation of the trigeminal and maxillary division of the right trigeminal nerve.
Magnetic resonance imaging of the brain showed an enhancing mass (5.5 × 4.8 × 5.5 cm3) in the right petroclival fissure involving the right cavernous sinus (Fig. 2). A second skin biopsy from the dorsum of the left hand demonstrated a combination of vacuolar interface dermatitis and dermal mucinosis consistent with dermatomyositis, lupus, or paraneoplastic dermatomyositis (Fig. 3).
Given the presence of a large central nervous system tumor, paraneoplastic dermatomyositis was thought to be the most likely diagnosis. Computed tomography of the chest, abdomen, and pelvis failed to disclose any other source of malignancy. A craniotomy for partial debulking and biopsy of the tumor was performed, revealing a myxoid chondrosarcoma, Grade II (Fig. 4A, B). Consistent with this diagnosis, immunostaining was positive for S100 (Fig. 4C) and negative for epithelial marker antigen and pancytokeratin.
The patient's prednisone dose was increased to 20 mg/day, and 6 weeks later, her diplopia resolved in primary gaze, with 1 mm of right ptosis and only mild limitation of abduction of the right eye. She also reported further improvement in her joint pain but still had persistent skin lesions and was transitioned from steroids to mycophenolate mofetil. She began adjuvant radiation therapy for her chondrosarcoma 4 months later. Her diplopia did not recur during a follow-up of 1 year.
Thirty percent of dermatomyositis cases are due to an underlying malignancy, but the majority of these are pulmonary or gynecological in origin (1,2). To our knowledge, there are no previous reports of a cavernous sinus tumor initially presenting with paraneoplastic dermatomyositis. Moreover, there is only 1 previous report of dermatomyositis secondary to chondrosarcoma that involved the tibia (3).
Dermatomyositis is a cutaneous disease with a myriad of skin findings, most classically Gottron papules of the interphalangeal areas of the fingers, or a heliotropic rash of the eyelids and cheeks. Proximal muscle weakness often is present (4). Laboratory findings for typically include elevated transaminases, aldolase, and creatinine kinase and the presence of anti-Mi-2 or anti-Jo antibodies (4). Normal creatinine kinase (5) and absence of anti-Mi2 or anti-Jo antibodies (6) may be more typical of paraneoplastic dermatomyositis and should prompt systemic workup for malignancy. Testing for additional antibodies, such as CA125, for ovarian tumors may be considered. An antibody that seems to be specific for cancer-associated dermatomyositis (“anti-155/140”) has been reported (7) but is not yet commercially available.
Our patient presented with skin eruptions, joint pain, and proximal muscle weakness. The cause of her signs and symptoms was not detected for 6 weeks until she underwent imaging for a right cavernous sinus syndrome, which revealed her malignancy. Laboratory tests for anti-Mi-2 and anti-Jo were negative, consistent with paraneoplastic dermatomyositis. Despite successful partial resection of her tumor, portions of her chondrosarcoma remained unresectable. This may explain the persistence of her skin lesions following surgery.
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