J Korean Foot Ankle Soc.  2019 Jun;23(2):74-77. 10.14193/jkfas.2019.23.2.74.

Fibroma of the Extensor Digitorum Longus and Extensor Digitorum Brevis Conjoined Tendon Sheath: A Case Report

• Park SJ
• Lee IG
• Cho Y

• KMID: 2449676
• DOI: http://doi.org/10.14193/jkfas.2019.23.2.74

Abstract

Fibroma of the tendon sheath (FTS) was initially described in 1936 by Geschickter and Copeland as a benign firmed soft tissue tumor that is rare and less common than another soft tissue tumors, especially giant cell tumors (GCT) of the tendon sheath. The common distinct feature is a slow-growing least painful rare entity arising from the tendon or tendon sheath. FTS is detected mostly in the fingers, hands and wrists but less commonly in the foot. Very few cases of FTS have been described arising from a flexor tendon of the foot. This article describes a 51-year-old patient with FTS that developed in the extensor tendon of the foot, which is the only known FTS to form in this area. Heterogeneous low signal intensity in both the T1- and T2-weighted images was observed in magnetic resonance imaging. The lesion was excised completely by open surgery. Histologically, it showed randomly arranged, fibroblast-like spindle cells in dense fibrous tissue and had insufficient hemosiderin-laden macrophages that are typical for GCT.

Keyword

Fibroma; Foot

MeSH Terms

Fibroma*
Fingers
Foot
Giant Cell Tumors
Hand
Humans
Macrophages
Magnetic Resonance Imaging
Middle Aged
Tendons*
Wrist

Figure

• 

  Figure 1 Magnetic resonance imaging (MRI) findings. (A) The tumor was well-defined heterogeneous low signal intensity on sagittal T1-weighted MRI image, located in the dorsal side of 2nd metatarsophalangeal (MTP) joint adjacent to the extensor digitorum longus (EDL) and extensor digitorum brevis (EDB). (B) The tumor shows same heterogeneous low signal intensity on sagittal T2-weighted MRI image. (C) Coronal T1-weighted MRI image revealing a mass firmly adherent to the dorsal side of 2nd MTP joint capsule and conjoined tendon of EDL and EDB. (D) The tumor on coronal T2-weighted MRI image shows same heterogeneous low signal intensity.

• 

  Figure 2 Gross photo. (A) Subcutaneous nodule protruded at dorsal side of 2nd metatarsophalangeal joint when patient flexion his toes. (B) At section, the mass appears to be white-tan, multilobular, and rubbery.

• 

  Figure 3 (A) Histologic image at low power showing a hypocellular mass of spindle cells within abundant collagenous stroma (H&E stain, ×40). (B) Histologic image at high power showing spindle cells with elongated nuclei, fine chromatin, small nucleoli, and eosinophilic collagenous stroma (H&E stain, ×100).

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