Case 31 Male, 49 years. Irregular pigmented lesion, skin of shoulderShow diagnosis & comments
(Largely in situ) lentiginous SAMPUS (superficial atypical melanocytic proliferation of uncertain significance), in association with intradermal naevus remnant
LENTIGINOUS SAMPUS (SO-CALLED 'LENTIGINOUS MELANOMA', 'LENTIGINOUS NAEVOID MELANOMA')
- Manifests as an irregular, variably hyperpigmented patch that is macroscopically similar to lentigo maligna
- May arise in skin lacking substantial solar damage.
- Stable in size for prolonged periods, or slow growth
- Most cases coming to clinical attention are from middle-aged or elderly individuals
- Local recurrence after incomplete or narrow-margin excision may occur
- Occasional progression to invasive superficial spreading melanoma NOS have been mentioned.
- No distant metastases have so far been documented to arise from this lesion
- Since distant metastasis has not beeen documented so far, I prefer not to call these lesions (lentiginous) melanomas, despite the fact that this term has become entrenched in the literature.
- In addition, many reported cases are entirely intraepidermal, which also makes the label of melanoma inappropriate.
- Since these are very superficial lesions (entirely intraepidermal, or compound lesions with a very superficial component) and more data regarding their possible malignant potential are required, I prefer to use the term introduced by Dr David Elder:
- SAMPUS (superficial atypical melanocytic proliferation of uncertain significance), lentiginous subtype.
- Elder DE, Xu X. The approach to the patient with a difficult melanocytic lesion. Pathology. 2004 Oct;36(5):428-34.
- King R. Lentiginous melanoma. Arch Pathol Lab Med. 2011 Mar;135(3):337-41.
- Weedon D. Lentiginous melanoma. J Cutan Pathol. 2009 Nov;36(11):1232.
- Mooi WJ. Lentiginous melanoma: melanoma subtype, or lentiginous SAMPUS? Adv Anat Pathol, in press.