Spitz naevus / Pigmented spindle cell naevus of Reed

Latest update 16/06/09

This chapter is set out as follows:

• Definition
• Key diagnostic features - clinical
• Dermoscopic features
• Pathology
• Management

Acknowledgement

Dr Jonathan Bowling (Consultant Dermatologist & Honorary Senior Clinical Lecturer, Department Dermatology, Churchill Hospital, Oxford) who has helped produce this article

Definition

• The Spitz naevus (syn. spindle cell naevus, epitheliod cell naevus, juvenile melanoma) is a variant of a compound naevus most commonly seen in children
• The pigmented spindle cell naevus of Reed (PSCNOR) is a variant of a compound or occasionally a junctional naevus. There is debate as to whether the PSCNOR is an entity in its own right or whether it is a variation of a Spitz naevus

Although both lesions are benign, difficulty can arise with histopathological assessment as they can be difficult to distinguish from an atypical Spitz naevus and a Spitzoid melanoma

Key diagnostic features - clinical

• Spitz naevus
  • Most common in children and young adults
  • The face is the most common site, but other areas can be affected
  • Raised, red and firm papular / nodular lesions. They can be pigmented
  • After an early period of relatively rapid growth to reach an approximate size of 1cm, lesions tend to become static around six months

• PSCNOR
  • Mainly present in young females
  • The thigh is the most common site
  • Regular, densely pigmented blue-black, palpable lesions measuring 5-10 mm in size

Dermoscopic features

• Spitz naevus
  • A dotted vascular pattern is typical for non-pigmented Spitz naevi
• PSCNOR There may be a variety of patterns:
  • Starburst pattern: this appears to be the most common presentation. It consists of a central pigmented grey-blue to black diffuse area with homogenously distributed streaks at the periphery. In most cases presenting in this way the histopathological findings are in keeping with a PSCNOR
  • Reticular pattern: a prominent, uniform dark brown to black network with frequent streaks at the periphery

• The following dermoscopic patterns may be present; however they should be interpreted with caution as they raise the possibility of atypical Spitz naevus or Spitzoid melanoma:
  • Globular pattern: a symmetric and predominantly globular pattern with a regular, discrete, brown to gray-blue pigmentation in the centre, and a characteristic rim of large brown globules at the periphery. Asymmetry of globules is a very suspicious feature
  • Negative (inverse) pigment network: a light-pigmented network with hyperpigmented areas within the network
  • Homogenous pattern: homogenous light brown or red-brown pigmentation without structures. Clinically the differential diagnosis would include an intradermal melanocytic naevus or an 'amelanotic / hypomelanotic' melanoma. A dotted vascular pattern may be detected. Histopathologically the findings are usually reported as a hypopigmented Spitz naevus
  • Atypical pattern: features can include asymmetry in colours and structures. Most of these lesions show a bizarre black, dark-brown, grey-bluish pigmentation. Pigment networks, globules and streaks are atypical and a blue-white veil has also been described. Dotted vascularisation has also been reported. These features cannot be distinguished from those found in melanoma

Pathology

• In the Spitz naevus cells may be spindle-shaped or epithelioid and arranged in clusters. Kamino bodies are found at the dermo-epidermal junction, but these are not specific for a Spitz naevus as they can also be found in early melanoma. In the PSCNOR large quantities of melanin are found in the naevus cells
• The following histopathological features may be found in a Spitzoid melanoma:
  • Upwards migration of naevus cells into the epidermis (pagetoid spread)
  • Pagetoid spread at the edge or beyond the lateral margin of the naevus
  • Although there may be a few mitotic figures in a Spitz naevus, the presence of larger numbers of mitotic figures is suspicious
  • Any mitotic figures in deeper cells
  • Any abnormal mitotic figures

Management

• Spitz naevi mimic melanoma, clinically, dermoscopically & histopathologically, and should therefore be referred to secondary care as a possible melanoma
• Lesions should be excised with a 2 mm margin. State clearly on the histology form that this is a Spitzoid tumour to aid the histopathologist

	Figure 1 – Spitz naevus on forearm
	Figure 2 – Spitz naevus
	Figure 3 – Dermoscopic appearance of figure 2 The redness of Spitz naevi is a vascular phenomena - gentle pressure as applied by a dermatoscope will often reduce the redness In this lesion dermoscopy shows little pigmentation and such features are similar to those found in an intradermal melanocytic naevus
	Figure 4 – Spitz naevus
	Figure 5 – Dermoscopic appearance of figure 4 Although there is a degree of variability seen in the morphological pattern towards the centre of the lesion, the general morphology is that of dotted vessels and is in keeping with a typical non-pigmented Spitz naevus
	Figure 6 - Pigmented spindle cell naevus of Reed (PSCNOR) above waist line (copied with kind permission of Dr Stephen Hayes)
	Figure 7 - Dermscopic appearance of figure 6 Reticular pattern
	Figure 8 - PSCNOR on forearm (copied with kind permission of Dr Eric Ersham)
	Figure 9 – Dermoscopic appearance of figure 8 The classical starburst pattern (copied with kind permission of Dr Eric Ersham)
	Figure 10 – PSCNOR on the thigh (copied with kind permission of Dr Eric Ersham)
	Figure 11 – Dermoscopic appearance of figure 10 Features again consistent with a starburst appearance, the asymmetrical nature of the lesion meant that careful histological evaluation was needed to confirm the diagnosis (copied with kind permission of Dr Eric Ersham)
	Figure 12 – PSCNOR
	Figure 13 – Dermosocopic appearance of figure 12 This lesions shows a globular pattern with the symmetrical arrangement of larger globules at the periphery
	Figure 14 - PSCNOR New lesion on dorsum of hand in a 23 year old woman
	Figure 15 - dermoscopic appearance of figure 14 Lesion shows a negative pigment network but with overall symmetry Negative pigment networks can also be found in melanoma
	Figure 16 – A case for discussion A new lesion on the thigh of a 23 year old woman
	Figure 17 – Dermoscopic appearance of figure 16 The presence of a blue white veil, irregular pigmentation and an asymmetrical vascular pattern is very suspicious and dermoscopically in keeping with a featureless melanoma Following initial excision with a 5mm clear margin, extensive pathological review failed to demonstrate melanoma and at MDT case review we felt the best description was an atypical Spitz naevus mimicking melanoma