LAUSR

To the Editor, Evaluation of excisional skin specimens is common in most dermatopathologists’ practice. It is usually straightforward, but on occasion, there may be challenges in confirming the presence or absence of a histopathologic process. This may be directly related to the biopsy procedure, that is, the choice of the hemostatic agent and the depth of the initial biopsy. In a dynamic dermatology clinic, physicians may opt for different hemostatic methods. During surgery, lidocaine with epinephrine, electrosurgery and suture ligation are preferred. However, even a shallow shave biopsy may lead to hemorrhage, especially if the patient has an abnormal coagulation status. More often than not, topical hemostatic agents are sufficient with the two most commonly used caustic agents: aluminum chloride (AlCl) and 20% ferric subsulfate (Monsel's solution). Their main role in hemostasis is through coagulating proteins, tissue necrosis, platelet activation, eschar and thrombus formation. Both Monsel's solution and AlCl have histologic features that may pose a diagnostic challenge. However, we have encountered several cases in which hemostasis-related changes have been helpful. Monsel's solution causes a pigmented fibrohistiocytic proliferation, which is beneath and/or extends horizontally from the prior biopsy site (Figure 1A). The collagen bundles show degenerative changes and are decreased in size. Coarse