PMC7271290_01
(a, b) Photograph of the patient at her first visit, with maximal external rotation of the shoulder (a), and photograph of the left axillary lump (b). Anteroposterior (c) and lateral (d) views on plain X-ray show a well-circumscribed, oval, osteolytic lesion with sclerotic margins in the lesser tubercle of the left humerus. (e) Contrast-enhanced computed tomography (CT) shows a soft tissue mass with invasion of the adjacent left humerus (arrow).
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fig1
Her physical examination revealed a hard, tender, palpable 6 x 5 cm mass with poor mobility under the left axilla and restricted movement of the left shoulder, especially external rotation (Figures 1(a) and 1(b)). Plain X-rays showed a well-circumscribed, oval, osteolytic lesion with sclerotic margins in the lesser tubercle of the left humerus (Figures 1(c) and 1(d)). Contrast-enhanced computed tomography (CT) showed a soft tissue mass with invasion of the adjacent left humerus (Figure 1(e)).
MRI images of the DFB in the left axilla with humeral invasion. (a-d) Raw axial images of the lesion with invasion of the underlying humerus. (e-h) Raw axial images of the lesion at its maximum diameter. (i-j) Raw coronal images of the lesion. First column (a, e), T1-weighted images. Second column (b, f), T2-weighted images. Third column (c, g, i), T2-weighted fat-suppression images. Fourth column (d, h, j), postcontrast T1-weighted images with fat suppression. The abbreviations: T1WI: T1-weighted images; T2WI: T2-weighted images; STIR: short TI inversion recovery; Gd: gadolinium-enhanced fat-suppressed T1-weighted images; Ax: axial images.
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The lesion had low signal intensity on T1- and T2-weighted images and short TI inversion recovery (STIR) (Figure 2). Mild internal enhancement was observed on gadolinium-enhanced fat-suppressed T1-weighted images (Figure 2).
(a) Microscopic image (hematoxylin-eosin (HE)) shows bland fibroblastic tumor cells and homogeneous hypocellular tissue, consistent with fibroedematous, hypovascular stroma. (b) FOSL1 immunohistochemistry.
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Histological examination revealed a uniformly paucicellular tumor consisting of widely spaced, bland, spindle- to stellate-shaped cells embedded in a myxocollagenous stroma (Figure 3(a)). Immunohistochemical analysis showed that the tumor cells were diffusely positive for FOSL1 (Figure 3(b)) and were negative for alpha-smooth muscle actin, desmin, CD34, beta-catenin, and S-100 (data not shown).
(a) Intraoperative photograph. A cavity was present in the lesser tubercle of the humerus. (b, c) Macroscopic appearance (b) and cut-surface view (c) of the tumor.
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The tumor was located in the patient's subscapularis muscle and invaded into the lesser tubercle of the left humerus, where a small cavity was observed after resection (Figure 4(a)). Macroscopically, the tumor was a well-circumscribed, firm, ovoid mass, while the cut surface was a homogeneously white-colored, solid mass (Figures 4(b) and 4(c)).