Case of the Month: The Blue-Gray Patches That Weren’t Hemochromatosis

A 48-year-old woman had blue-gray patches on her forehead, cheeks, and the backs of her hands for three years. Slowly spreading. No pain, no itch, no ulceration. Just a strange, persistent discoloration that didn’t fit anywhere obvious.

Her clinicians ran through the usual suspects: exogenous ochronosis, hemochromatosis, Addison disease, drug-induced pigmentation from something like minocycline or amiodarone. Each one plausible. None of them quite right.

The Pathology Told a Different Story

A punch biopsy of the dorsal hand settled it. Fine, dark-brown to black granules were scattered through the papillary and superficial reticular dermis — not primarily clustered around the eccrine glands the way textbooks usually describe, but decorating the dermal elastic fibers instead. That distribution alone is a detail most trainees never get taught to look for.

A Fontana-Masson stain lit the granules up strongly positive — but before jumping to “melanin,” it’s worth remembering that Fontana-Masson isn’t specific for melanin at all. It detects an argentaffin reaction: a substance’s ability to reduce silver salts on its own, without any external reducing agent. Melanin does this. So does metallic silver. A negative iron stain ruled out hemosiderin, and the clinical history did the rest.

Diagnosis: Argyria — chronic silver deposition in the skin, most often from colloidal silver supplements, silver-containing topical products, or occupational exposure.

Why This One Is Worth Knowing

Argyria is one of those diagnoses that’s easy once you’ve seen it and easy to miss if you haven’t. The teaching point that made this case worth writing up: the classic “periadnexal basement membrane” pattern isn’t the whole picture. Elastic fiber decoration is well documented in the literature and can dominate the histology, exactly as it did here — so anchoring only on eccrine glands is a real way to talk yourself out of the right answer.

There’s also a genuine clinical stake in getting this differential right. Unlike argyria, hemochromatosis and Addison disease carry real systemic implications. A quick, correct read on the special stains can spare a patient an unnecessary work-up — or trigger the right one.

This is the first entry in DiSK’s Case of the Month — a monthly spotlight pulled from real sign-outs, picked for the teaching point buried inside, not just the diagnosis on the label. New cases go up regularly in the Case Library; this series highlights the ones worth slowing down for.