An 8-year-old girl came to the pediatric myositis clinic with a 4-month history of right arm pain and weakness in both legs; she could not easily rise from a seated or squatting position. The pain was rated 5 of 10 and described as achy without radiation, tingling, or numbness. There was no history of trauma or infection preceding the pain. Previously independent, she now required help dressing. Her mother denied a change in voice, acquisition of a nasal tone, and dysphagia. One month earlier, she had developed pain in her hips, ankles, and knees that was exacerbated by activity but had no joint swelling or fevers. A history of infections and surgeries was denied. She was born after 35 weeks' gestation to nonconsanguineous parents. Family history was positive for celiac disease in her father and thyroid problems in her paternal grandfather and paternal aunt. In addition, the maternal grandmother had both bipolar disease and colon cancer. Her father was Hispanic, and her mother was Taiwanese. She lived with both parents and a 12-year-old brother. Her immunizations were up to date. Review of systems revealed only that she had always had frigid fingers, which turned purple with cold exposure. She denied weight loss or decreased appetite.
Her temperature was 36.6°C, respiratory rate was 24 breaths per minute, blood pressure was 101/56 mm Hg, pulse was 95 beats per minute, height was 145.6 cm (>97th percentile), and weight was 30.7 kg (90th percentile). She was alert and in no acute distress. Her ears, nose, eyes, and throat were normal except for mild erythema in the medial canthus of the right eye without vessel dilation. There was no lymphadenopathy. Cardiac examination was notable for mild systolic 2/6 murmur at the left upper sternal boarder, which changed with change in position. Her lungs were clear bilaterally with good aeration. Her abdomen was soft with dullness to percussion in the right upper quadrant, and she had mild pain on deep palpation of both the lower right and left quadrants. Genitourinary evaluation was normal. Her skin had erythematous papulomacular lesions on the elbows, knees, and medial aspect of the ankles (). The malar or heliotrope characteristic of JDM was absent, but she did have erythema of the distal digits, most pronounced around the nail beds of the fingers, as well as the proximal and distal interphalangeal joints (). Neither tight skin nor digital ulcers were present. On musculoskeletal examination, she had flexion contractures of her elbows and limited extension of both knees and ankles with pain on movement but no joint swelling. Compression of the proximal lower muscles produced complaints of tenderness. Neurologic examination was notable for muscle weakness (neck flexors [3 of 5], upper proximal [4 of 5], and lower extremity [3 of 5]) and core weakness (she was unable to perform a sit-up unassisted). She had hip and thigh weakness, using her hands and arms to ″walk″ up her body from a squatting position (positive Gower maneuver).
FIGURE 1 A, Medial aspect of the left ankle, showing a papular, circular area of mild erythema (~3 × 2 cm) on a more erythematous base. B, Both hands at diagnosis with erythema of the distal digits, most pronounced around the nail beds of the fingers, (more ...)
Laboratory evaluation with a complete blood and white blood cell count revealed 5580/μL (normal range: 4500–13 500/μL) (53.5% polymorphonuclear cells, 31.8% lymphocytes, 6.8% eosinophils, 7.2% mononuclear cells [which was not characteristic for JDM], and 0.7% basophilic cells), a hemoglobin level of 12.7 g/dL (normal range: 12–16 g/dL), hematocrit at 37.1% (normal range: 36%–46%), and a platelet count of 298 000/μL (normal range: 150 000–450 000/μL). Her creatine kinase (440 IU/L [normal range: 49–199 IU/L]) and aldolase (11.7 U/L [normal range: 3.4–8.6 U/L]) levels were mildly elevated, but she had normal levels of aspartate aminotransferase (38 IU/L), alanine aminotransferase (9 IU/L), and lactate dehydrogenase (274 IU/L). Rheumatologic evaluation included a positive antinuclear antibody test result (1:5120 titer), speckled pattern (normal: <80 titer), myositis-associated and -specific antibodies that showed indeterminate Mi-2, with the others negative, including p155/140 elevated immunoglobulin G (IgG) (1440 mg/dL [normal range: 608–1229]) and IgE (409 kU/L [normal: <160 kU/L]) levels, and normal levels of IgM and IgA. Her neopterin level was elevated at 20 nm/L (normal: <10 nm/L). Complement concentrations were normal (C3: 97.4 mg/dL; C4: 21.3 mg/dL). Peripheral blood flow cytometry revealed decreased numbers of natural killer cells (CD3−
) (absolute count: 89 [normal range: 138–1027]), a decreased number of CD3 cells, and normal numbers of B cells. Nail-fold capillary end-row loops (ERLs) were decreased at 5.42 ERLs per mm (normal: ≥6.8 ERLs per mm).6
MRI revealed abnormally increased T2-weighted signal compatible with inflammatory infiltration within nearly all of the muscles of the thighs bilaterally (), consistent with dermatomyositis, and a complex round mass in the left side of the pelvis. Ultrasound findings indicated a teratoma (a solid avascular left ovarian mass with increased echogenicity), which suggested a significant fat component. The ovarian mass was surgically removed, and the biopsy confirmed the presence of a mature ovarian teratoma without immature components. It should be noted that the muscle biopsy did not indicate JDM, because it only displayed mild variability in fiber size but no perifascicular atrophy, perivascular inflammation, or loss of intramuscular capillaries. Her symptoms and abnormal laboratory results resolved without immunosuppressive therapy by 4 months after surgical removal of the teratoma.
FIGURE 2 MRI with fat suppression of the patient's proximal lower extremities, which revealed an increased T2-weighted signal in many of the muscles of the thighs bilaterally. The wide arrow points to the darker, more normal muscle tissue, and the thin arrows (more ...)