Ex Vivo Dermoscopy for Biobank-Oriented Sampling of Melanoma FREE

• Autores: Josep Malvehy, Paula Aguilera, Cristina Carrera, Gabriel Salerni, Louise Lovatto, Alon Scope, Ashfaq A. Marghoob, Josep Palou, Llucia Alós, Susana Puig Sardá
• Localización: JAMA Dermatology, ISSN 2168-6068, Vol. 149, Nº. 9, 2013, págs. 1060-1067
• Idioma: inglés
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• Resumen

  • mportance In the era of targeted therapy for cancer, translational research identifying molecular targets in melanoma offers novel opportunities for potential new treatments.

    Objectives To describe a method for sampling fresh tissue from primary melanoma and to test whether the area of maximal thickness can be identified with dermoscopy to ensure it remains available for routine histopathological diagnosis.

    Design, Setting, and Participants Tumors clinically suspicious for melanoma with diameter exceeding 5 mm were included. Dermoscopy-guided sampling was performed using a 2-mm to 3-mm punch through not the thickest part of the tumor. In vivo and ex vivo dermoscopic images obtained were available to the diagnosing pathologist. Melanoma samples were obtained in a referral melanoma unit.

    Main Outcomes and Measures In study 1, Breslow thickness in 10 melanomas was compared between sampled tissue and the remaining specimen to confirm that the area of maximal thickness remained available for the histopathological diagnosis. In study 2, forty-three additional melanomas were sampled for biobanking prospectively. Agreement between 2 independent observers on dermoscopic identification of the thickest part of the melanoma was studied.

    Results In study 1, the area of maximal Breslow thickness in all 10 melanomas was not sampled and remained in the main specimen. In study 2, sampling was performed by one of the investigators. Concordance was 93% between 2 independent observers for the dermoscopic selection of the thickest portion of the melanoma. Pathologists asserted that the sampling procedure did not compromise their ability to evaluate melanoma specimens. A limitation is that this is a single-center study. Each case required joint evaluation by expert dermoscopists and dermatopathologists.

    Conclusions and Relevance In applying the dermoscopy-guided sampling protocol, we make the following 5 recommendations: Samples should only be obtained from areas that will not interfere with the pathologist’s diagnosis and prognostic information. Sampling should not be obtained from tumors for which one suspects that the histopathological evaluation may prove difficult. Sampling should not be performed on small melanomas; we recommend a minimum diameter of 10 mm. All the dermoscopy-guided sampling should be documented with images, available to pathologists and clinicians, and reflected in the pathology report. Finally, the frozen biobank samples should be made available for routine hematoxylin-eosin histopathological evaluation until the final pathology report is produced. Ex vivo dermoscopy may serve to guide the procurement of small samples from primary melanoma for fresh tissue biobanking without compromising the histopathological evaluation.

    In the era of targeted therapy for cancer, translational research identifying molecular targets in melanoma offers novel opportunities for potential new treatments. There is increasing evidence at the molecular level that melanoma is composed of distinct mutational subsets,1 each harboring different potential targets for therapy.2 Fresh or frozen tissue is required for the performance of cellular studies (including tissue cultures from primary tumors) and molecular studies (including genomics and proteomics) and for the design and production of biologic treatments. The aforementioned studies cannot be adequately conducted on formalin-fixed, paraffin-embedded samples.3,4 Needless to say, the development of fresh-frozen tissue banks procured from primary melanomas will likely lead to heightened translational research and may greatly influence diagnosis, prognosis, and therapeutic strategies in the coming years.

    Histopathological study of formalin-fixed, paraffin-embedded specimens is crucial for the diagnosis and staging of melanoma.4,5 The risk in randomly procuring samples from freshly excised melanoma specimens for biobanking is that the remaining specimen, which is submitted for formalin-fixed, paraffin-embedded examination, could sustain damage that would preclude adequate histopathological processing. In addition, the random removal of tissue may compromise the ability of the pathologist to evaluate and adequately diagnose the remaining specimen on routine histopathological examination, with untoward clinical and medicolegal consequences.6,7 In a previous study,8 researchers evaluated a method for the procurement of fresh tissue from excisional specimens of melanocytic nevi based on examination with the naked eye; they concluded that the procurement of fresh tissue for research had no influence on the final diagnosis. A method has been described for the use of ex vivo dermoscopy for gross pathological evaluation in the histopathology laboratory.9 Subsequently, ex vivo dermoscopy was used in 517 cutaneous biopsy specimens,10 determining that it provides useful ancillary information for the histopathological diagnosis of melanocytic neoplasms. Indeed, dermoscopy can be useful for guiding tissue sectioning for the histopathological correlates,11- 18 and certain dermoscopic structures can be used to predict melanoma thickness.19,20 Given the added value of dermoscopy for performing gross pathological evaluation of melanocytic neoplasms and for predicting microscopic findings on the histopathological examination, we reasoned that dermoscopy can be used to select areas within excisional specimens that could be safely removed for molecular studies without compromising the histopathological evaluation of the specimen. This idea prompted us to explore the use of dermoscopy as an ancillary method for guiding and precisely documenting the procurement of fresh tissue from primary melanoma excisional specimens for molecular research.