A novel 2-hour method for rapid preparation of permanent paraffin sections when treating melanoma in situ with mohs micrographic surgery.
BACKGROUND
Distinguishing sun-induced melanocyte atypia from residual melanoma in situ (MIS) can be challenging, particularly when working with frozen sections. Immunostains such as melanoma-associated antigen recognized by T cells (MART-1) can assist, but paraffin sections provide an optimal means of analyzing melanocyte morphology.


OBJECTIVE
To verify the effectiveness of a 2-hour paraffin processing technique that uses microwave technology in the preparation of MIS sections.


METHODS
Twelve MIS debulk specimens were divided into 4 pieces with each piece processed 1 of 4 ways: our 2-hour paraffin technique with hematoxylin and eosin (H&E), conventional 24-hour paraffin processing with H&E, frozen sections with H&E, and frozen sections with MART-1 immunostaining. A Mohs surgeon and a dermatopathologist compared all specimens in a blinded fashion using a 3-point ranking scale to assess ease of visualizing normal melanocytes, ease of visualizing abnormal melanocytes, and overall ability to adequately visualize epidermal and dermal structures.


RESULTS
A nonparametric signed rank test indicated no significant differences between our microwave technique and conventional paraffin processing in all 3 criteria (p=.29, .63, .75, respectively). Our microwave technique was significantly better than frozen H&E sections for all 3 criteria (p=.046, .004, .005, respectively).


CONCLUSIONS
This rapid microwave tissue processing technique is comparable with conventional paraffin section processing.
Mallipeddi
Raj
R
Dermatological Surgery and Laser Unit, St John's Institute of Dermatology, St Thomas' Hospital, London, UK.
Stark
Jeff
J
Xie
Xian-Jin
XJ
Matthews
Mark
M
Taylor
R Stan
RS
D006801:Humans; D008545:Melanoma / Q000473:pathology* / Q000601:surgery*; D015580:Mohs Surgery; D016612:Paraffin Embedding / Q000379:methods*; D010865:Pilot Projects; D011446:Prospective Studies; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery*; D013997:Time Factors