Sea urchin spines in the stratum corneum: an early finding related to trauma.

Penetrating trauma from sea urchin (Echinoidea) spines has been shown to cause numerous cutaneous reactions, ranging from initial pain that rapidly dissipates and resolves to chronic inflammation and formation of characteristic sea urchin granulomas. Many of these skin-colored or violaceous papules and nodules form weeks to months after injury, and may be surgically excised. Histopathologic examination commonly shows well-defined granulomas, the majority of which represent sarcoidal-type granulomas. Other microscopic patterns, such as foreign body reactions and chronic inflammation, have also been shown. Retained spine fragments are birefringent on polarized microscopic examination and are most likely found in the dermal layer. Herein, we describe a case of traumatic sea urchin cutaneous injury with a unique early cutaneous trauma reaction in a young male who lived in Hawaii. Histopathologic exam was significant for retained spines in the layer of the stratum corneum, but no signs of granulomatous inflammation were observed. This case report emphasizes the unique features of our case and reviews the common clinical and histopathologic features of sea urchin cutaneous reactions.