Ann Dermatol.  2020 Feb;32(1):64-68. 10.5021/ad.2020.32.1.64.

Schwannoma Presenting as a Scalp Mass: A Case Report with Magnetic Resonance Imaging Findings

• Park JS
• Moon J
• Cho SI
• Mun JH

• KMID: 2467203
• DOI: http://doi.org/10.5021/ad.2020.32.1.64

Abstract

A schwannoma can develop anywhere along the course of nerves. However, a schwannoma presenting as a scalp nodule is rare. Here, we present a rare case of schwannoma on the scalp with a review of magnetic resonance imaging (MRI) findings, which was initially misdiagnosed as an epidermal cyst or vascular malformation despite various radiologic examinations. Recognition of characteristic MRI features of schwannomas, such as low signal margin, target, entering-and-exiting-nerve, and fascicular signs, may result in an accurate diagnosis and proper management of tumors. In this report, we summarized differential characteristics of a schwannoma with an epidermal cyst and a lipoma.

Keyword

Magnetic resonance imaging; Nerve sheath neoplasms; Neurilemmoma; Scalp; Skin neoplasm

MeSH Terms

Diagnosis
Epidermal Cyst
Lipoma
Magnetic Resonance Imaging*
Nerve Sheath Neoplasms
Neurilemmoma*
Scalp*
Skin Neoplasms
Vascular Malformations

Figure

• 

  Fig. 1 (A) Clinical photography of subcutaneous protruding mass on the left occipital scalp before surgery. (B, C) Successful removal by exploratory surgery. We made a zigzag-line incision and elevated the flaps for a visual field to remove the entire mass. (D) Clinical photography of scalp 12 months after surgery. There was no recurrence of the mass until 12 months follow-up.

• 

  Fig. 2 (A) Gross specimen of multilobulated mass measuring 7.0×2.7×1.0 cm3. (B) Histologic examination shows an encapsulated, wellcircumscribed mass that included alternating Antoni A and Antoni B (hematoxylin and eosin [H&E], ×40). (C) Tumor cells are positive with S-100 (×40). (D) Acellular areas lying between opposing rows of parallel nuclei (verocay body) are seen (H&E, ×400).

• 

  Fig. 3 Magnetic resonance imaging findings. (A) A T1-weighted sagittal image, (B~D) T2-weighted transverse images, and several characteristic features of a schwannoma: low signal margin (red arrows), target sign (yellow arrow), entering-and-exiting-nerve sign (green arrowheads), and fascicular sign (blue arrows).

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