Skin melanocytic tumor
Spitzoid neoplasms, BAP1 inactivated neoplasms, and deep penetrating nevi
Pigmented spindle cell nevus of Reed


Topic Completed: 1 February 2013

Minor changes: 15 January 2021

Copyright: 2002-2021, PathologyOutlines.com, Inc.

PubMed Search: Pigmented spindle cell nevus

Christopher S. Hale, M.D.
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Cite this page: Hale CS. Pigmented spindle cell nevus of Reed. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumormelanocyticpigmentedspindlecellnevus.html. Accessed March 4th, 2021.
Definition / general
  • First described by Reed in 1975
  • Heavily pigmented nevus, often recent onset, widely considered a Spitz nevus variant (J Am Acad Dermatol 1993;28:565)
  • Clinically and histologically simulates melanoma
Terminology
  • Also called Reed's nevus
Epidemiology
Sites
Clinical features
  • < 1 cm, solitary, deeply pigmented and well circumscribed maculopapule
  • Clinically resembles melanoma
Case reports
Treatment
  • Conservative but complete excision
  • Does not recur
Dermoscopy
  • Two patterns reported:
    1. Brown to blue pigmentation with peripheral rim of large brown globules (globular pattern)
    2. Dark diffused pigmentation and pseudopods regularly distributed at periphery in stellate or radiate pattern (starbust pattern, Dermatol Online J 2004;10:5)
Clinical images

AFIP images

Small and
symmetrical
lesion differs
from Spitz nevus



Images hosted on other servers:

Rim of brown globules around lesion

Pseudopods arranged regularly

Small multicolored lesion

Slightly raised dark lesion

Microscopic (histologic) description
  • Some similarity with Spitz nevi
  • Symmetric with cytologic maturation
  • Nests and fascicles of spindled melanocytes along dermoepidermal junction and within dermal papillae
  • May be junctional or compound
  • Expansive, not infiltrative growth pattern
  • Extends no deeper than reticular dermis
  • Nevus cells typically contain abundant melanin pigment, may be associated with melanophages
  • Nuclei are monotonous, resemble normal keratinocytes and may have small nucleoli
  • Often has architectural or cytologic atypia (Hum Pathol 1991;22:52)
  • Variable lymphocytic infiltrate at base of lesion
  • Variable transepidermal elimination of junctional nests
  • No / rare mitotic figures
  • Note: hypopigmented variant is similar but without abundant melanin (J Cutan Pathol 2008;35 Suppl 1:87)
Microscopic (histologic) images

AFIP images

Various images



Images hosted on other servers:

Various images

Symmetric pigmented tumors (figs 6 - 9)


Symmetric pigmented tumor

Pigmented spindle cell tumor

Positive stains
  • HMB45 highly expressed in intraepidermal component of pigmented spindle cell nevus (PSCN) and spindle cell melanoma but dermal component negative in PSCN, irregularly positive in spindle cell melanoma (Am J Surg Pathol 2011;35:1733)
  • Other melanocytic markers (S100, MelanA)
Molecular / cytogenetics description
Videos

Pigmented spindle cell nevus

Differential diagnosis
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