Editor's Note: When melanoma is suspected clinically, it is essential, when feasible, to excise the neoplasm completely. It also is crucial to submit the entire specimen to a pathology laboratory in order that sections can be cut from it across the breadth of it. In this way, a histopathologist can assess the neoplasm comprehensively and can optimize the likelihood of accurate diagnosis.

Biopsy specimens of pigmented lesions removed by excision and submitted to pathology laboratories often pose challenges to histotechnologists charged with responsibility for processing them in preparation for diagnosis by histopathologists based on sections cut from them. The challenge becomes even greater whenever markings of ink or sutures have been placed by surgeons in an effort to orient elliptical specimens removed by excision. A precise method for grossing such biopsy specimens is needed if histopathologists are to be provided with unambiguous directions in regard to the "coordinates" of the specimen and to assessment of margins of excision of a particular lesion.

After the specimen is measured, the location of the suture(s) established, and the size of the pigmented lesion recorded, the dermis is permeated thoroughly with blue and black dyes* (Fig. 1A). It is important to filter these dyes before they are applied to the specimen in order to remove a crystallized sediment that inevitably forms after they have been stored for long periods of time. Inadvertent introduction of this crystalline material into tissue may cause artifacts during microtomy. The specimen is then grossed in "breadloaf" fashion into segments no more than 3 mm thick. This facilitates penetration of various solvents and paraffins into the tissue during processing (Fig. 2).

As each segment from the excised specimen is prepared, a small dab of red dye is placed on the side of the section that will face upward when the tissue is embedded in paraffin (Fig. 3). This enables the microtomist to section each block that houses tissue in a manner that ensures consistency in orientation.

During assessment of margins of excision by microscopy, the numbered tissue segments, the two-colored tissue stains, and the location of the marking suture provide the histopathologist with "coordinates" that permit the exact location of the lesion vis-à-vis the margins of the specimen (Fig. 4). For example, if, in Figure 1A, the long suture represents the medial pole and the short suture the inferior margin, the histopathologist is able to "map" with accuracy the involved margins across the entire specimen. Thus, in the diagram (Figs. 2-4), "2-blue" designates a margin on the superior border near the medial pole to which neoplastic cells extend. This information enables a surgeon to perform a subsequent procedure logically, thereby ensuring that no more tissue is removed than necessary.