"BAPoma" - BAP1-inactivated nevus/melanocytoma - mimic of nevoid melanoma (AIP France 2021-case 12)
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- Опубліковано 10 вер 2024
- This video is an excerpt from my one-day dermpath course in Paris, France, on October 8, 2021, for the Academie Internationale de Pathologie - Division Française (IAP French division).
Full 5 hour video of the entire course is available for free here: kikoxp.com/pos....
Digital slide (H&E): kikoxp.com/pos...
Digital slide (BAP-1 immunostain): kikoxp.com/pos...
Video: kikoxp.com/pos...
Handout & figure images: kikoxp.com/pos...
A complete organized library of all my videos, digital slides, pics, & sample pathology reports is available here: kikoxp.com/pos... (dermpath) & kikoxp.com/pos... (bone/soft tissue sarcoma pathology).
Please check out my Soft Tissue Pathology & Dermatopathology survival guide textbooks: bit.ly/2Te2haB
This video is geared towards medical students, pathology or dermatology residents, or practicing pathologists or dermatologists. Of course, this video is for educational purposes only and is not formal medical advice or consultation.
Presented by Jerad M. Gardner, MD. Please subscribe to my channel to be notified of new pathology teaching videos.
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This video is an excerpt from my one-day dermpath course in Paris, France, on October 8, 2021, for the Academie Internationale de Pathologie - Division Française (IAP French division).
Full 5 hour video of the entire course is available for free here: kikoxp.com/posts/8361.
Digital slide (H&E): kikoxp.com/posts/7016
Digital slide (BAP-1 immunostain): kikoxp.com/posts/8126
Video: kikoxp.com/posts/8504
Handout & figure images: kikoxp.com/posts/8505
You are the best Dr. Garner. You are so down to earth
Here is a 23 bullet summary of the talk (generated with assistance of AI)
1. The passage discusses a case of a 16-year-old boy with a skin-colored papule on the scalp, which upon examination appears to be a combined nevus or melanocytic lesion with two components - a conventional nevus at the periphery and a more cellular nodular component in the middle.
2. The passage suggests that this could be a melanoma growing out of a background nevus, which is a concern, especially in a young patient. However, the lack of an obvious in-situ component in the epidermis is somewhat reassuring.
3. A BAP1 immunostain is performed, which shows loss of nuclear staining in the central nodular component, while the peripheral conventional nevus retains the staining. These lesions with BAP1 loss have been called "BAP1-inactivated nevi" or "BAP-omas" (a slang term).
4. The passage discusses the molecular basis of these lesions, involving a BRAF mutation leading to the initial nevus formation, followed by BAP1 loss in the central component. This can occur sporadically or in patients with a germline BAP1 abnormality, which is associated with various tumor risks.
5. Dr. Fouchardiere, an expert on the topic, is invited to share his insights. He explains the concept of "melanocytomas" in the WHO classification, which are intermediate lesions between nevi and melanoma.
6. He describes the progression from low-grade melanocytomas, which are BAP1-inactivated nevi with low mitotic activity and peripheral chronic rate under 5%, to high-grade melanocytomas with increased nuclear atypia and density.
7. Dr. Fouchardiere has seen over 300 cases of BAP1-inactivated tumors in his career, including over 20 cases that progressed to become truly malignant melanomas and even some metastatic cases.
8. Remarkably, he has been fortunate enough to find cases where all four stages - conventional nevus, low-grade melanocytoma, high-grade melanocytoma, and malignant melanoma - can be seen progressing on the same slide.
9. He describes being able to visualize the progression from the typical nevus, to the low-grade melanocytoma with loss of BAP1, then to the high-grade melanocytoma with increased nuclear atypia and density, and finally to the frank malignant melanoma with mitotic activity.
10. Dr. Fouchardiere notes that he has even been able to correlate these morphological changes with corresponding changes in the molecular profiles, as demonstrated by comparative genomic hybridization (CGH) showing increasing clonality as the lesions progress.
11. While the majority of BAP1-inactivated lesions are expected to behave in a benign fashion, Dr. Fouchardiere's extensive experience highlights that a subset can indeed progress to metastatic melanoma, emphasizing the importance of close follow-up and appropriate management.
12. He has seen around 10 metastatic cases develop from BAP1-inactivated tumors over the span of a decade in his practice.
13. Dr. Fouchardiere recommends routine genetic counseling and germline BAP1 testing, especially in patients with multiple BAP1-inactivated lesions, as this may indicate an underlying germline predisposition syndrome.
14. Patients with germline BAP1 abnormalities are at risk for various tumors, including uveal melanomas, mesotheliomas, and others, underscoring the importance of genetic testing and counseling.
15. The passage highlights that around 10-15% of BAP1-inactivated lesions are expected to be associated with an underlying germline BAP1 syndrome, while the majority are sporadic cases in otherwise normal individuals.
16. Dr. Fouchardiere notes that patients with the germline BAP1 syndrome often develop multiple BAP1-inactivated lesions, which can serve as a clinical clue to their underlying predisposition.
17. He has observed cases where the four stages of progression (nevus, low-grade melanocytoma, high-grade melanocytoma, and melanoma) can be seen simultaneously on the same slide, providing a unique window into the stepwise evolution of these lesions.
18. The passage underscores the importance of collaboration between pathologists, experts like Dr. Fouchardiere, and genetic counselors in accurately diagnosing and managing these complex melanocytic lesions with molecular abnormalities.
19. Genetic counselors are praised for their expertise in navigating the complex issues surrounding molecular testing and helping patients understand the potential impact on family planning and future decisions.
20. The passage discusses the importance of recommending genetic counseling not just for testing, but also to understand the implications and ethical considerations of germline testing, especially in younger patients.
21. The role of pathologists is highlighted as gatekeepers in identifying potential problems and recommending appropriate specialist care and counseling for patients with complex conditions.
22. Additional insights are shared on the staining patterns of other markers (p16, MART-1, HMB-45) in BAP1-inactivated lesions, further elucidating the diagnostic features of these entities.
23. Overall, the insights shared by Dr. Fouchardiere provide a rare and invaluable glimpse into the spectrum of BAP1-inactivated tumors, from their benign inception to their potential for malignant progression, and highlight the need for careful monitoring and a multidisciplinary approach to patient care.
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I love the way you explain. It was awesome
Thank you so much Jerad! I had to make a presentation on BAPomas and wasn't understanding anything before this video. Greetings from Santiago, Chile :)
De nada, amiga!
Superb Dr. Jerad 🎉
I am happy to be in company of so learned people like you
thank you
Great discussion ！
Sorry sir. It's here.