Pathological demonstration of rapid involvement into the subcutaneous tissue in a case of fatal hydrofluoric acid burns

We report an autopsy case of a man who suffered accidental chemical burns following exposure to 60% hydrofluoric acid. The extent of the burns covered about 30% of his body surface, and cardiopulmonary arrest occurred about 30min after the exposure. At autopsy, the skin of the affected area showed greenish gray or black coloring with thin circumferential erythema, and this discoloration extended as far as the periosteum of the skull. However, such discoloration was not found on the mucosa of the airway or the gastrointestinal tract. Microscopically, severe liquefactive necrosis was already evident on the skin. Elastic fibers within the dermis were completely lost, and the entire wall of large vessels within the subcutaneous layer was already severely affected. Blood analysis in the emergency room showed hypocalcemia, and the levels of fluoride ions in the postmortem blood and urine showed extremely high values. However, fewer fluoride ions were detected from the lung tissue. The present case suggests that the hydrofluoric acid had immediately penetrated down into the deep layer of the skin, thereby involving the large vessels present within the subcutaneous layer. These pathological findings of the skin seen in the present case explain the mechanism behind the rapid dissemination of fluoride ions which entered the bloodstream from damaged arteries, resulting in the development of acute toxicity.