PMC3661435_01
Preoperative Diagnostic Imaging. (A) Axial contrast enhanced CT illustrating left intraconal soft tissue mass (B) Coronal CT of infiltrative mass inseparate from inferior and lateral rectus muscles. (C) Axial T1 weighted-image (WI) without contrast with intraconal mass hypointense to orbital fat (D) Axial T1 WI with fat suppression and contrast demonstrates hetereogenous enhancement (E) Coronal T2 WI demonstrates hyperintense signal with irregular borders and mass effect on the left optic nerve.
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There was no obvious bone involvement (Fig. 1).
Intraoperative photograph, surgeon's view, depicting diffuse nature of tumor, approached using a bone-sparing infero-lateral orbitotomy.
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The patient underwent an inferior-lateral orbitotomy via swinging eyelid incision (Fig. 2), after a fine needle aspiration biopsy revealed "neoplastic cells of an undetermined origin." An indistinct purple mass with the consistency of friable mucosa intermixed with stringy mucoid-like material was encountered and dissected in a piecemeal fashion from the orbital fat with pituitary forceps.
Histological appearance of orbital myxoma (A) Myxoid lesion around skeletal muscle (H and E stain x 40) (B) Spindle cells with nuclear atypia and rare binucleated cells at higher magnification (H and E stain x 400) (C) Vimentin (DAKO, Carpinteria, California) immunostain positive, confirming mesenchymal origin of tumor. (immunohistochemical stain x 100).
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Histopathological examination of the mass revealed a myxoid lesion around extraocular skeletal muscle. (Fig. 3A) The lesion exhibited a patternless yet focal and fascicular spindle cell neoplasm with short tapering nuclei and indistinct cytoplasm. (Fig. 3B) These cells were distributed in a copious myxoid matrix containing a small number of capillaries.
Postoperative MRI (2 months) (A) Axial T1 image with mild residual signal between left optic nerve and lateral rectus. (B) Axial T2 with residual high signal probably representing residual myxoma.
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The patient has been followed with serial examinations and MR imaging for 3 years without recurrence (Fig. 4).