Hematoxylin-eosin–stained sections showed degeneration of collagen fibers and a deposition of round to oval, ochrelike amorphous substance within the dermis. Ultramicroscopic examination revealed both intact and partly degenerated collagen fibers and the deposition of an amorphous, electron-dense substance.
The patient was also noted to have urine that darkened on exposure to air. Radiography of the skeletal system demonstrated a characteristic picture of severe arthropathy with narrowing of the intervertebral, articular spaces and calcification of the disks. The clinical diagnosis was confirmed by the detection of homogentisic acid (HGA) in the urine specimen by thin-layer chromatography (excretion rate, 11.64 mmol/d). Some improvement in the patient's arthralgia was observed after administration of nonsteroidal anti-inflammatory drugs (eg, diclofenac, 50 mg 3 times a day) and physiotherapy.
Extensive Bluish Gray Skin Pigmentation and Severe Arthropathy. Arch Dermatol. 2000;136(4):547-552. doi: