First dilemma in diagnosis is recognition. As<unk> s often present on severely sun-damaged skin, it is frequently found amongst numerous pigmented lesions – thin seborrheic keratoses,<unk>  senilis,<unk> nes. It is difficult to distinguish these lesions with the naked eye alone, and even with some difficulty using dermatoscopy. As the<unk>  is often very large, it often merges with, or encompasses other skin tumors – such as<unk> nes, melanocytic nevi, and seborrheic keratosis. Second dilemma is the biopsy technique. Even though excisional biopsy (removing the entire lesion) is ideal, and advocated by pathologists; practical reason dictates that this should not be done. These tumors are often large and presenting on the facial area. Excision of such large tumor would be absolutely contraindicated if the lesion's identity is uncertain. The preferred method of diagnosis is by using a punch biopsy, allowing the physician to sample multiple full thickness pieces of the tumor at multiple sites. While one section of the tumor might show benign melanocytic nevus, another section might show features concerning for severe cellular atypia. When cellular atypia is noted, a pathologist might indicate that the entire lesion should be removed. It is at this point that one can comfortably remove the entire lesion, and thus confirm the final diagnosis of<unk> . The size of the punch biopsy can vary from 1 mm to 2 mm, but it is preferable to use a punch 1.5 mm or larger. Representative samples of the most atypical parts of the nevus should be biopsied, often guided by dermatoscopy. Image:Lentigo<unk>  - very high mag.Light microscopy of<unk>  showing the characteristic atypical epidermal melanocytes. H&E stain. File:SOX10 immunohistochemistry of<unk> .Immunohistochemistry with SOX10 (staining the cell nuclei of melanocytes) facilitates diagnosis of<unk> , in this case showing an increased number of melanocytes along stratum basale of the skin, and nuclear pleumorphism. The changes are continuous with the resection margin (inked in yellow, at left), conferring a diagnosis of a not radically removed<unk> . File:Lentigo<unk>  Melanoma Left Central Malar Cheek.Lentigo<unk>  Melanoma, Left Central Malar Cheek marked for biopsy
Lentigo maligna
Lentiginosis
Extramammary Paget's disease
Lymphomatoid papulosis
Acral lentiginous melanoma
Nodular melanoma
Nevus sebaceous
Ductal carcinoma in situ