Skin melanocytic tumor
Topics to be merged
Lentiginous nevus
Author: Christopher S. Hale, M.D.
Topic Completed: 1 February 2017
Minor changes: 4 April 2019
Copyright: 2003-2019, PathologyOutlines.com, Inc.
PubMed Search: lentiginous nevus[title]
Table of Contents
Definition / general | Terminology | Epidemiology | Clinical features | Case reports | Treatment | Clinical images | Microscopic (histologic) description | Microscopic (histologic) images | Differential diagnosisCite this page: Hale C Lentiginous nevus. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticlentiginousmelanocyticnevus.html. Accessed August 8th, 2020.
Definition / general
- Common type of agminate (clustered) nevus with multiple pigmented macules or papules within a pigmented patch (Cutis 2007;80:465, eMedicine - Speckled Lentiginous Nevus)
- May be congenital or acquired (Arch Dermatol 2001;137:172)
Terminology
- Also called "speckled lentiginous nevus" (see also speckled lentiginous nevus) or "nevus spilus"
- NOT related to "acral lentiginous nevus" (see acral nevi)
Epidemiology
- Speckled lentiginous nevus syndrome: hyperhidrosis, muscular weakness, dysesthesia or other neurological abnormalities
Clinical features
- Often benign mole with increase in size, formation of irregular borders or peripheral change in color
- May be due to "reactivation" of radial proliferation
- Usually 5 mm or less
- Note: atypia often present in childhood acral lesions (Pediatr Dev Pathol 1998;1:388)
Case reports
- 42 year old man with speckled lentiginous nevus on trunk (Dermatology 2004;209:228)
- 45 year old man with melanoma (Int J Dermatol 2006;45:1362)
Treatment
- Excision of speckles or entire lesion
Clinical images
Images hosted on other servers:
Macular hyperpigmentation and superimposed darker macules
Speckled lentiginous nevus
Adjacent type with a thick hypertrichotic inferolateral portion
Admixed type hypertrichotic hybrid nevus
Large unilateral speckled lentiginous nevus
Extensive speckled lentiginous nevus
Microscopic (histologic) description
- "Shoulder" area of lentiginous junctional melanocytic proliferation beyond lateral border of underlying dermal nevus
- Elongation of rete ridges with small nests of melanocytes at tips of rete
- Individual unit melanocytes extending along sides of rete, often mild lymphohistiocytic infiltrate with pigment incontinence
- No atypia, no pagetoid spread and no dermal fibrosis
- Acral lesions: resemble dysplastic nevus due to elongation of rete ridges, continuous proliferation of melanocytes at dermoepidermal junction, single scattered melanocytes or less commonly small clusters within the upper epidermis; poor or absent lateral circumscription, melanocytes with abundant pale cytoplasm and round / oval, sometimes hyperchromatic nuclei and prominent nucleoli present at the dermoepidermal junction; however, unlike dysplastic nevi, they lack anastomosing rete ridges, cytological atypia and well-formed lamellar fibroplasia (Histopathology 1995;27:549)
- Variants:
- Macular variant: "jentigo" pattern (lentiginous pattern plus nests of melanocytes at dermal-epidermal junction) in the darker speckles and by some nests of melanocytes at the dermoepidermal junction at the tips of the papillae, but background pigmentation has microscopic features of lentigo; tan-brown background with dark flat speckles in relatively even distribution resembling polka dots; associated with phacomatosis pigmentovascularis
- Papular variant: dermal or compound melanocytic nevi; light-brown macule superimposed by multiple melanocytic nevi in the form of papules or nodules that show a more uneven distribution reminiscent of a star map; small dark macules may be present; associated with phacomatosis pigmentokeratotica or speckled lentiginous nevi syndrome (Dermatology 2006;212:53)
Microscopic (histologic) images
Images hosted on other servers:
Nests of small and monomorphic melanocytes at the
dermoepidermal junction and within the reticular
dermis, with many melanocytes concentrated around
blood vessels and adnexal structures
Elongated rete ridges and lentiginous proliferation
of melanocytes at the dermal-epidermal junction
Prominent basal layer pigmentation similar to that
seen in lentigo simplex
Differential diagnosis
- Dysplastic nevus
- Lentigines - no nests, may be nevi if examine serial sections (Am J Dermatopathol 1985;7 Suppl:5)
- Superficial spreading or lentiginous melanoma - pagetoid lateral spread, mitotic activity in deep dermis and no maturation (Mod Pathol 2005;18:1397)
