A 57-year-old Thai woman presented with proximal muscle weakness and significant weight loss for 1 month. Physical examination revealed non-tender, ill-defined, erythematous plaques with hyperpigmentation on face, upper chest wall, and neck; which the patient said the lesions had appeared for 1 year. Motor power was grade III at all proximal muscles of arms and legs. 

Questions: 

1.What is the provisional diagnosis? 

2.What are the other physical signs that you should look for?

3.What is the most proper next step investigation?

โดย น.อ.หญิง สัญสณีย์  พงษ์ภักดี หัวหน้าหน่วยประสาทวิทยา กองอายุรกรรม รพ.ภูมิพลอดุลยเดช พอ.

ANSWERs 

1.What is the provisional diagnosis? 

• Seen erythematous plaque with hyperpigmentation at V-area, posterior part of neck and cheek (V-sign, shawl sign, facial rash) 
• Suspect inflammatory myositis from dermatomyositis or paraneoplastic dermatomyositis 
• Differential diagnosis:  inflammatory myositis from CTDs (SLE, systemic sclerosis) or systemic vasculitis (ANCA-associated vasculitis) or overlapping syndrome 

2.What are the other physical signs that you should look for?

• Associated signs in anti-TIF1-gamma DM:  Red-on-white patch, psoriasiform plaques 
• Other DM signs:  Heliotrope, gottron's sign/papule, mechanic's hand, hiker's feet, periungual erythema, linear extensor erythema, holster's sign, vasculitic skin lesions, skin ulcers, hyperkeratotic palmar papules, inverse gottron papule
• Signs of overlapping syndrome:  malar rash, DLE, oral ulcer, non-scarring alopecia, sclerodactyly, skin thickening / tightening, bound-down skin, arthritis, velcro sounds, loud P2 
• Evidence of malignancy:  organomegaly, abnormal lung / breast / abdominal / pelvic mass, lymphadenopathy, cervical or nasopharyngeal mass 

3.What is the most proper next step investigation?

• Muscle enzymes (CPK, AST, ALT, LDH, aldolase)
• Myositis profile, suspecting anti-TIF1-gamma Ab 
• CXR for evaluation the presence of ILD 
• Work up for malignancy, especially CA lung and CA nasopharynx in Asian population
• Investigations for diagnosing extramuscular involvement of DM and overlapping CTDs

References:  

Oldroyd A, Sergeant JC, New P, McHugh NJ, Betteridge Z, Lamb JA, et al. The temporal relationship between cancer and adult onset anti-transcriptional intermediary factor 1 antibody–positive dermatomyositis. Rheumatology. 2018;58(4):650-5

Rheumatology 7th edition 2018 Marc C. Hochberg, MD, MPH, MACP, Alan J. Silman, Josef S. Smolen, MD, et al.

โดย น.ท.หญิง อินทิรา  อุไรเลิศ  อาจารย์หน่วยโรคข้อและรูมาติสซั่ม

กองอายุรกรรม โรงพยาบาลภูมิพลอดุลยเดช กรมแพทย์ทหารอากาศ