PMC4065691_01
Left perineal mass. Examination of the vagina reveals a bulging mass through the left wall of the vagina but without any direct invasion. Examination of the rectum revealed normal tone with displacement of the left lateral rectal wall towards the midline.
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A 40-year-old African American, morbidly obese female patient was referred to our service for evaluation of left buttock mass (Figure 1).
MRI sagittal plane. 23 cm (craniocaudal) mass exhibits midrange T2 weighted signal superiorly with diminished T2 weighted signal at its inferior position. White arrow showing the mass abutting the posterior wall of the vagina. Dashed arrow showing the rectum wall.
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The MRI dimensions of the mass were 23 x 8 x 11 cm and showed no muscular or osseous invasion, with well-defined walls and considerable enhancement with a preliminary diagnosis of a pedunculated leiomyoma; however, a soft tissue sarcoma could not be ruled out (Figure 2).
Resected mass measuring 24 x 12 x 8 cm with smooth tan-pink surface and weighting 1660 gm. On sections, the mass shows areas of smooth, whorled tan-white tissue, with areas of cystic degeneration, edema, and rare slightly softer, white opaque areas. No hemorrhage or necrosis is identified grossly.
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During surgery, an ellipsoid well-circumscribed mass measuring 24 x 12 x 8 cm was noted without invasion to surrounding tissue (Figure 3).
Hematoxylin-eosin staining of tumor section showing well-differentiated smooth muscle cells with eosinophilic cytoplasm and bland, blunt-ended nuclei (40x).
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These cells had eosinophilic cytoplasm and mostly bland, uniform, cigar-shaped nuclei, resembling normal smooth muscle cells (Figure 4).
Morphology and Immunohistochemical staining of tumor; HE: hematoxylin-eosin, HEX10 (low power field), HEX40 (high power field), Desmin (positive), SMA: smooth muscle actin (positive), ER: estrogen receptor (positive), PR: progesterone receptor (positive), CD34 (negative), and CD117 (negative).
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Immunohistochemistry showed that these tumor cells were positive for desmin, smooth muscle actin, estrogen receptor, and progesterone receptor and negative for S100, CD117, and CD34, confirming the smooth muscle origin of the tumor (Figure 5).