J Korean Soc Radiol.  2017 Aug;77(2):129-132. 10.3348/jksr.2017.77.2.129.

Ultrasonographic Findings of Pilar Sheath Acanthoma: A Case Report

• Kang DJ
• Lee SJ
• Kim SJ

• KMID: 2386751
• DOI: http://doi.org/10.3348/jksr.2017.77.2.129

Abstract

Pilar sheath acanthoma is a rare benign follicular hamartoma that presents with a central sinus containing keratinous material and is lined by epithelium. It typically occurs on the face, especially on the upper lip and forehead. In our case, the ultrasound (US) feature of pilar sheath acanthoma revealed a well-defined, oval hypoechoic nodule with hypoechoic capping within the dermis over the medial aspect of the calf. To the best of our knowledge, despite many reports on the clinicopathological aspects of pilar sheath acanthoma, this entity has not been well described in the radiologic literature, and US findings have not been documented. We report the US findings of a case of pilar sheath acanthoma on the calf.

MeSH Terms

Acanthoma*
Dermis
Epithelium
Forehead
Hair Follicle
Hamartoma
Lip
Skin Neoplasms
Ultrasonography

Figure

• 

  Fig. 1 Pilar sheath acanthoma on the right calf in a 56-year-old man. A, B. Photograph of the leg. Medial (A) and close-up (B) views of the papule on the right calf. A solitary, erythematous to hyperpigmented papule with a central punctum (arrow in A) is seen on the medial aspect of the right leg. C. Gray scale ultrasonography shows a 0.65 × 0.35 cm, well-defined oval hypoechoic nodule (arrows) with hypoechoic capping (arrowheads) within the dermis over the medial aspect of the right calf. D. A color Doppler image shows internal hypervascularity within the nodule. E. A photomicrograph (hematoxylin-eosin stain, × 10 ) shows a lobular patulous tumor that was connected to the epithelium and the dermis. F. A photomicrograph (hematoxylin-eosin stain, × 200) shows tumor cells consisting of mixed blue-gray (infundibular) and pink (isthmic) corneocytes. The findings are compatible with pilar sheath acanthoma.

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