A biopsy specimen of a papule revealed a normal epidermis with a mild perifollicular lymphocytic infiltrate (Figure 2). There was increased dermal mucin dispersed between collagen bundles, as highlighted with a colloidal iron stain. Laboratory evaluation revealed an antinuclear antibody titer equal to or greater than 1:160 (speckled pattern); a VDRL slide test result of 1:2, with a negative fluorescent treponemal antibody absorption test result; and an elevated anticardiolipin antibody titer. Complement levels were within normal limits. Serologic tests were negative for antibodies to anti-DNA, ribonuclear protein, Sm, Ro, and La. Urinalysis showed rare white and red blood cells, trace blood, and 2+ protein. A 24-hour urine study revealed nephrotic-range proteinuria at 2760 mg/d (normal, ≤150 mg/d). A renal ultrasound failed to show any gross abnormalities. A renal biopsy specimen revealed mesangial lupus nephritis; therefore, prednisone and azathioprine therapy was initiated. With treatment, the patient's renal function improved and the mucinous papules involuted.
Hypopigmented Papules and Nodules on the Trunk and Arms—Diagnosis. Arch Dermatol. 2004;140(1):121-126. doi:10.1001/archderm.140.1.121-f