Fast Five Quiz: Skin Cancer

William James, MD


January 04, 2019

Guidelines on the diagnosis and treatment of Merkel cell carcinoma were released in 2015 by a collaborative group of multidisciplinary experts from the European Dermatology Forum, the European Association of Dermato-Oncology, and the European Organization of Research and Treatment of Cancer. Diagnostic guidelines included the following:

  • Clinical features of the cutaneous/subcutaneous nodules contribute little to the diagnosis of Merkel cell carcinoma

  • The diagnosis is made by histopathology, and an incisional or excisional biopsy is mandatory

  • Immunohistochemical staining contributes to clarification of the diagnosis

  • Initial workup consists of ultrasonography of the locoregional lymph nodes and total-body scanning examinations

  • In patients without clinical evidence of regional lymph node involvement, sentinel node biopsy is recommended, if possible, and will be taken into account in a new version of the American Joint Committee on Cancer classification

Although less than a quarter of melanomas are initially diagnosed during routine office examinations, those that are found by physicians tend to be thinner. Thus, a regular full-body cutaneous examination by the primary care provider is crucial to diagnosis at an early stage. The entire cutaneous surface of the head and neck should be examined, paying particular attention to sun-exposed areas.

For larger lesions or those located in cosmetic or functionally critical areas, confirming the diagnosis is often preferable before embarking on surgical excision that may be extensive and require reconstruction. In these cases, an incisional or punch biopsy should be performed initially, with further treatment based on the pathology results. Whichever biopsy method is chosen, the following principles should be observed:

  • The biopsy should contain the full thickness of the skin in order to evaluate the depth of the lesion; therefore, a shave biopsy is generally not recommended when malignancy is suspected

  • The biopsy should be centered over the transition point between normal and involved skin, thereby providing a reference for comparison by the pathologist

  • When possible, incisions should be made parallel to the natural lines of skin tension (Langer lines) for optimal cosmetic outcome

  • For punch biopsies, stretching the skin perpendicular to the Langer lines creates an ellipse oriented in this optimal direction and facilitates closure

To accurately and definitively diagnose BCC of the eyelid, histological confirmation is required and is most commonly obtained through shave or punch biopsy, which provides information regarding the histological subtype of BCC. Cytology does provide a rapid alternative that may yield and even help confirm a diagnosis during the initial visit; however, its sensitivity in diagnosing BCC of the eyelid is unknown. It is not considered to be sufficiently sensitive in planning surgical management.

For more on the workup of Merkel cell carcinoma, read here.


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