Lentigo maligna melanoma is a melanoma that has evolved from a lentigo maligna,: 695  as seen as a lentigo maligna with melanoma cells invading below the boundaries of the epidermis. They are usually found on chronically sun damaged skin such as the face and the forearms of the elderly. Lentigo maligna is the non-invasive skin growth that some pathologists consider to be a melanoma-in-situ. A few pathologists do not consider lentigo maligna to be a melanoma at all, but a precursor to melanomas. Once a lentigo maligna becomes a lentigo maligna melanoma, it is treated as if it were an invasive melanoma. Presentation
An invasive tumor arising from a classical lentigo maligna. Usually a darkly pigmented raised papule or nodule, arising from a patch of irregularly pigmented flat brown to dark brown lesion of sun exposed skin of the face or arms in an elderly patient. Diagnosis
The first problem is difficulty. As lentigo malignas often present on severely sun damaged skin, it is frequently found amongst numerous pigmented lesions – thin seborrheic keratoses, lentigo senilis, lentigines. It is difficult to distinguish these lesions with the naked eye alone, and even with some difficulty using dermatoscopy. As the lentigo maligna is often very large, it often merges with, or encompasses other skin tumors – such as lentigines, melanocytic nevi, and seborrheic keratosis. The second difficulty   is the biopsy technique. Even though excisional biopsy (removing the entire lesion) is ideal, and advocated by pathologists, practical considerations may indicate that this should not be done.
In October 2017, the FDA approved a generic version, which is manufactured in India by Natco Pharma, and imported and sold by Dutch firm Mylan. In February 2018, Sandoz received FDA approval for their generic version. In parallel with the development and approval processes, the generic competitors have disputed Tevas newer patents, any of which if upheld, would prevent marketing of long-acting generics.While the patent on the chemical drug expired in 2015, Teva obtained new US patents covering pharmaceutical formulations for long-acting delivery. Litigation from industry competitors in 2016-2017 resulted in the new patents being judged invalid. In October 2018, the U.S. Court of Appeals for the Federal Circuit upheld the patent invalidation for obviousness. The case reflects the larger controversy over evergreening of generic drugs. References
Further reading
"Glatiramer acetate". Drug Information Portal. U.S. National Library of Medicine.