Israel Medical Association Journal

Almost three-quarters of a century ago an American surgeon named Frederick Edward Mohs, had the idea of excising skin cancers and examining the margins before the closure of the surgical wound. In this manner he thought the patient would get better treatment with the best cosmetic result.

Mohs micrographic surgery (MMS) in its present format has been used as a surgical method for treating skin cancers for the last 70 years. The method became popular with American dermatologists 54 years ago when the original Mohs technique was modified into its fresh tissue modality [2] and in the rest of the Western world and Israel more than 35 years ago. Variations of MMS started to appear and indications for surgery also expanded. At the beginning, MMS was indicated mainly for basal and squamous cell carcinomas–nonmelanoma skin cancers (NMSC). Knowledge has been collected and today the method is applicable for a variety of other skin cancers such as melanoma in situ, microcystic adnexal carcinoma, dermatofibrosarcoma protuberans (DFSP), and other adnexal and spindle cell tumors. In this issue of the Israel Medical Association Journal (IMAJ), Landov and colleagues [3] showed the value of MMS for the treatment of DFSP.

Background: Solid organ transplant recipients (SOTRs) are at increased risk for both skin and internal malignancies (IM). The risk of IM after the occurrence of non-melanoma skin cancer (NMSC) has been studied in the general population but very little is known about this association in SOTRs.

Objectives: To evaluate the risk of IM following a prior diagnosis of post transplantation NMSC in SOTRs.

Methods: This single center retrospective cohort study included a study population of 329 SOTRs from Rabin Medical Center who had a post-transplant diagnosis of skin malignancy, internal malignancy, or both from 2012 to 2018.

Results: In total, 135 (41.03%) SOTRs were diagnosed with IM without a preceding diagnosis of NMSC while only 42 (12.76%) patients diagnosed with IM had a preceding diagnosis of NMSC. SOTRs with a diagnosis of NMSC showed a significantly decreased risk of developing subsequent IM (hazard ratio [HR] 0.64, 95% confidence interval [95%CI] 0.44–0.94, P = 0.02) compared to those without a prior NMSC diagnosis. Liver and lung transplant patients showed a significantly decreased risk of developing subsequent IM after a diagnosis of NMSC (HR 0.09 and 0.43, respectively). When stratified by type of IM, only patients who were diagnosed with a hematological malignancy had a significantly lower risk of developing this malignancy if they had a prior NMSC (HR 0.26).

Conclusions: The findings of this study suggest a protective effect of NMSC on subsequent IM in the organ transplant population.

Background: Skin basal and squamous cell carcinomas together account for over half of all newly diagnosed cancer cases. Frozen  section control of surgical margins is often required in the head and neck region. A paraffin permanent section does not always confirm the results of a frozen section.

Objectives: To test the diagnostic accuracy of frozen section histopathological analysis in determining the free margins of excised tumors.

Methods: This was a retrospective study of 169 cutaneous basal and squamous cell carcinomas excised with surgical margins diagnosed by frozen section and confirmed by permanent paraffin sections. The data included patients' age, gender, clinical and histopathological diagnosis, as well as characteristics of the lesions.

Results: There were 149 (88%) basal cell carcinomas and 20 (12%) squamous cell carcinomas. False negative margins were found in 19 cases (11.2%) and false positive margins in 11 cases (6.6%). We did not find any correlation between false positive or false negative margins and patients' age, gender, tumor size, tumor location, or the presence of sun-damaged skin. A significantly lower rate of false negative results was found in the residual tumor group.

Conclusions: Our findings show support the use of frozen section margin control in selected patients suffering from non-melanoma skin cancer of the head and neck.