Calcific panniculitis and nasopharyngeal cancer-associated adult-onset dermatomyositis: a case report and literature review

Panniculitis is an uncommon cutaneous manifestation in dermatomyositis. It not only occurs in idiopathic dermatomyositis, but also rarely occurs in the setting of malignancy-associated dermatomyositis. Calcinosis cutis is also less likely to be found in adult-onset dermatomyositis. In malignancy-associated dermatomyositis, panniculitis can precede, concur, or follow the diagnosis of malignancy. We report the case of a 26-year-old Thai female with calcific panniculitis in the setting of adult-onset dermatomyositis associated with nasopharyngeal cancer. The clinical course of calcific panniculitis in our case was not parallel to the course of malignancy. Calcific panniculitis can appear many years after, despite the remission of the cancer. A thorough review of the previously reported literature is also provided.


Introduction
Panniculitis is an uncommon cutaneous manifestation in dermatomyositis. Since 1924, fewer than 30 cases of panniculitis-associated dermatomyositis have been reported. It not only occurs in idiopathic dermatomyositis, but also rarely occurs in the setting of malignancyassociated dermatomyositis (Girouard et al. 2012). To our knowledge, only 4 cases of panniculitis in the setting of malignancy-associated dermatomyositis have been documented.

Case report
A 26-year-old Thai female presented with Gottron's papules, heliotropes, and proximal muscle weakness for 3 months. Investigations showed elevation of creatine phosphokinase, lactic dehydrogenase, and positive antinuclear antibodies (ANA) at the titer of 1:320 (fine speckled pattern). However, negative results were found for anti-dsDNA, anti-Sm, anticardiolipin antibodies, and antiβ 2 glycoprotein1antibodies. Lupus anticoagulant and complement level (C3, C4) were normal. Myositisspecific and associated antibodies, including anti-Mi2, anti-Ku, anti-PM-Scl-100, anti-PM-Scl-75, anti-Jo-1, anti-PL-7, anti-PL-12, anti-Ro-52, anti-SRP, anti-EJ, and anti-OJ, were all negative. Electromyography (EMG) study demonstrated increased duration of small polyphasic motor unit action potential (MUAP) with early motor unit recruitment, which is compatible with myositis. With 4 of 5 Bohan and Peter diagnostic criteria (Bohan and Peter 1975a, b) for dermatomyositis being met, a diagnosis of dermatomyositis was made without performing muscle biopsy. The patient was treated with chloroquine 250 mg/day, azathioprine 100 mg/day, and prednisolone 30 mg/day. One month after diagnosis of dermatomyositis, our patient was found to have a posterior pharyngeal wall mass and was diagnosed as non-keratinizing nasopharyngeal carcinoma stage IV (T3N3bN0). Following a course of concurrent chemoradiation, nasotelescopy was performed and remission of the malignancy was confirmed. Two years after remission, Gottron's papules, heliotropes, and muscle power improved, but she developed an ill-defined indurated plaque on her right arm. There was no history of previous trauma to the area. Magnetic resonance imaging (MRI) then revealed diffuse inflammatory process involving skin along right upper arm to proximal forearm, with underneath subcutaneous fat necrosis and marked skin thickening. Five months later, she experienced progressive hardening of skin on her arms, legs, and abdomen. On physical examination, there were multiple, nontender, fixed, hard-to-bony consistency, dermal to subcutaneous nodules and plaques on axillae, arms ( Figure 1), legs, and left lower quadrant of abdominal wall. The lesions varied in size from 1.5 to 5 cm and were mild tender on palpation. Plain radiographs showed softtissue calcification along extremities ( Figure 2). A biopsy of subcutaneous nodule on her right upper extremity revealed calcification, degeneration of subcutaneous fat cells, and septal fibrosis underneath basal vacuolar degeneration with melanin incontinence and dermal mucin deposition ( Figure 3). Lipomembranous change was observed in subcutaneous fat. Serum calcium and phosphate level were normal. Colchicine 0.6 mg/day was initiated for the treatment of calcinosis, without significant change in the lesions.

Discussion
Adult patients with dermatomyositis are more likely to develop panniculitis than children. Clinical presentation includes painful subcutaneous nodules, indurations, plaques, and/or lipoatrophy. The presence of panniculitis may precede, concur, or occur up to 5 years after diagnosis of dermatomyositis. Table 1 shows characteristics of documented cases of adult-onset dermatomyositis-associated panniculitis. In our case, the patient developed indurated plaques on her arms 2 years after being diagnosed with dermatomyositis.
Although panniculitis is an uncommon presentation in adult-onset dermatomyositis, microscopic changes in adipose tissue were more common than clinically observed (Chao and Yang 2000;Girouard et al. 2012). Panniculitis was found in up to 7% of skin biopsy specimens from poikilodermatous skin change in dermatomyositis patients (Janis and Winkelmann 1968). Among dermatomyositis cases that had panniculitis, lobular panniculitis with lymphoplasmacytic infiltration, lipomembranous panniculitis, and calcific panniculitis were reported (Girouard et al. 2012;Yamamoto et al. 2007). Consistent with the review by Solans et al. (2002), our case demonstrated degeneration of subcutaneous fat cells, septal fibrosis, and lipomembranous change in subcutaneous tissue underneath basal vacuolar degeneration at the dermoepidermal junction.
In malignancy-associated dermatomyositis, panniculitis can develop from 14 months prior to the diagnosis of malignancy to 4 months after the diagnosis of malignancy (Girouard et al. 2012). Reported associated malignancies include parotid carcinoma, rhabdomyosarcoma, and ovarian adenoma (Girouard et al. 2012). In our case, panniculitis and skin calcinosis occurred 2 years after the diagnosis of nasopharyngeal carcinoma.
In contrast to panniculitis in dermatomyositis, calcinosis cutis is less likely to be found in adult-onset than in juvenile-onset dermatomyositis. Calcinosis cutis presents in up to 20% of adult-onset cases, as compared to 70% of juvenile-onset dermatomyositis cases (Gutierrez and Wetter 2012). Extremities and trunk are the common sites    of involvement (Gutierrez and Wetter 2012). Panniculitis is considered the preceding manifestation of the calcific process in dermatomyositis. In our case and consistent with this tendency, there was history of diffuse inflammatory process involving skin along the right arm, with MRI confirming soft tissue inflammation and subcutaneous necrosis prior to the development of calcification. This is consistent with dystrophic calcification. Severity of dystrophic calcification in dermatomyositis ranges from localized small subcutaneous nodules, tumoral deposits, and intramuscular and fascial calcification to severe forms of exoskeleton formation (Gutierrez and Wetter 2012;Reiter Reiter et al. 2011).

Conclusion
In conclusion, we report the first documented case of calcific panniculitis with lipomembranous change in the setting of adult-onset dermatomyositis associated with nasopharyngeal cancer. The clinical course of our case was not parallel to the course of malignancy. Calcific panniculitis can appear many years after, despite the remission of cancer. However, the association between calcific panniculitis and malignancy-associated dermatomyositis cannot be ascertain by a single case report. Further study and larger case series are needed.

Consent
Informed consent was obtained from the patient for the publication of this report and any accompanying images.