PMC4533353_01
Axial plain (A) and contrast-enhanced (B) computed tomography images showing an extracranial mass in the left temporal region. No tumor stain was observed on anteroposterior (C) and lateral (D) angiography with contrast injection from left common carotid artery. Axial T1-weighted (E), T2-weighted (F), fat-suppression (G), and contrast-enhanced (H) magnetic resonance images showing an extracranial mass in the left temporal region.
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F1
Computed tomography (CT) of the head revealed a well-defined, extracranial, subcutaneous mass with a smooth and clear border that separated it from the surrounding tissues (Fig. 1A). The lesion consisted of a homogeneous low-attenuating component that was heterogeneously enhanced with contrast (Fig. 1B). T1-weighted images (Fig. 1E) and hyperintense on T2-weighted images (Fig. 1F), and revealed heterogeneous enhancement after gadolinium injection (Fig. 1H). The tumor signal was not suppressed on fat-suppression images (short T1 inversion recovery: STIR; Fig. 1G), indicating that the tumor did not have fat-rich components. Because the tumor showed enhancement, angiography was performed to evaluate the vascularity of the tumor, which revealed a poorly vascularized mass without any tumor stain (Fig. 1C, D).
A: Gross appearance of a surgical specimen. B: Photo-micrograph of a surgical specimen showing bland spindle and stellate cells separated by extracellular myxoid matrix. Hematoxylin and eosin stain, original magnification x 100.
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F2
The resected tumor, which was soft, gelatinous, and lobulated, measured 6.5 x 4.0 x 3.0 cm and contained encapsulated nodules (Fig. 2A). A diagnosis of intramuscular myxoma was confirmed on the basis of the histological examination (Fig. 2B), which revealed a monotonous, hypovascular, myxoid stroma with randomly scattered spindle and stellate cells along with striated muscle fibers.