Dear Editor,
Deep angiomyxoma (DAM) is an uncommon soft tissue tumor which is usually seen in the perineum and pelvis.1 The tumor is characterized by loosely arranged spindle to stellate cells in a richly vascular myxoid stroma.2 The tumor was initially described as aggressive angiomyxoma in 1983 as the case series documented a tendency for the lesion to recur locally due to the infiltrative nature, which curtailed complete resection.2 By the next decade, the hormonal dependence of the tumor was discovered which can be demonstrated by the expression of estrogen and progesterone receptors by immunohistochemistry. Exploiting the hormonal dependence, came the idea of treating these tumors with gonadotropin releasing hormone (GnRH).3 We discuss a rare case of DAM arising from the bladder wall which was treated effectively with GnRH analog following initial debridement.
A 47- year old female patient presented to the surgical out-patient department with lower abdominal pain and poor urinary stream for six months. Per vaginal and per rectal examination showed a firm extraluminal mass on the left lateral wall of pelvis. Her hematological and biochemical parameters were within normal limits. Contrast-enhanced computed tomography (CECT) showed homogenous contrast enhancement without necrotic areas (Fig. 1A). A Magnetic resonance imaging (MRI) showed a large poorly defined multilobulated lesion measuring 11.3 × 11.5 × 14.8 cm in the pelvis possibly originating from the pelvic floor which appeared hypointense on T1 weighted image and hyperintense on T2 weighted image sequences. The lesion was causing compression and displacement of rectum and sigmoid colon posteriorly and toward right side with preserved fat planes (Fig. 1B). Uterus and urinary bladder were displaced anterolaterally toward the right side with preserved fat planes. Tumor marker screening showed normal values (CEA: 1.52 IU/L, AFP:1.69 IU/L, Beta HCG: 0.116 IU/L, CA 125: 7.56 IU/L, and CA 19.9: 8.1 IU/L). With these findings, a CT-guided trucut biopsy was done which was suggestive of a benign spindle cell lesion. To relieve the patient of the mass effect, she was taken up for exploratory laparotomy. Per operatively, a 10 × 8 × 8 cm tumor was seen in the pelvic cavity arising from the wall of urinary bladder and partial resection of the mass along with total abdominal hysterectomy with bilateral salpingo-oophorectomy was done. Macroscopic examination of the mass showed a poorly circumscribed tumor (5 × 2.5 × 4 cm) that was soft, rubbery with cut section showing myxoid whitish areas admixed with areas of hemorrhage (Fig. 2A). She also had an intramural fibroid in the fundus of uterus measuring 1 × 1 × 1 cm.
Fig. 1.
(A) Pre-operative computed tomography image showing a homogenous contrast enhanced lesion posterior to the bladder wall. (B) Pre-operative magnetic resonance image showing a hyperintense pelvic mass with preserved fat planes. (C) Post-operative computed tomography image showing residual homogenous contrast enhanced lesion adherent to the bladder wall.
Fig. 2.
(A) Cut surface of the mass shows a homogenous myxoid lesion (B) and (C) (Hematoxylin & Eosin stain magnification 40× ‘B’, magnification 100× ‘C’) microscopy shows hypocellular tumor composed of spindle to stellate cells interspersed in a loose edematous myxoid stroma. Delicate collagen fibers and numerous scattered variably sized thin to thick walled vessels are seen. (D) (Periodic acid Schiff's with Alcian blue stain magnification 400×) Microscopy highlights the magneta colored collagen fibers and bluish acidic myxoid ground substance. (E) Immunohistochemistry (Magnification 400×) with estrogen receptor (EP1 clone, Pathnsitu) shows nuclear expression in the stromal cells. (F) Immunohistochemistry (magnification 400×) with Desmin (D33 clone, Pathnsitu) shows cytoplasmic expression in the stromal cells.
On microscopy, the mass was composed of a hypocellular tumor composed of spindle to stellate cells interspersed in a loose edematous myxoid stroma. The tumor cells had scant pale eosinophilic cytoplasm, small uniform nuclei, and small indistinct nucleoli. The stroma was composed of delicate collagen fibers and numerous haphazardly scattered variably sized vessels with thin to thick walls. Perivascular cuffing of collagen and extravasated erythrocytes were seen (Figs. 2B and C). No mitosis or necrosis was seen. The tumor was seen to reach up to the cauterized margins of resection. A periodic acid Schiff's-Alcain Blue stain highlighted the magenta-colored collagen fibers and bluish acidic myxoid ground substance (Fig. 2D). Immunohistochemistry showed the spindle to stellate cells to stain for estrogen receptor (faint, nuclear) (EP1 clone, RTU, Pathnsitu), progesterone receptor (intense, nuclear) (EP2 clone, RTU, Pathnsitu), Desmin (cytoplasmic) (D33 clone, RTU, Pathnsitu), smooth muscle actin (cytoplasmic) (1A4 clone, RTU, Pathnsitu), and vimentin (cytoplasmic) (V9 clone, RTU, Pathnsitu). On the basis of the histology and immune-phenotype, a diagnosis of deep (aggressive) angiomyxoma was made. The uterus showed atrophic endometrium with an intramural leiomyoma. The cervix, both ovaries, and fallopian tubes showed normal histomorphology. The postoperative period was uneventful and the patient was started on GnRH analogs, in view of the subtotal resection. A repeat CECT after 04 months showed significant reduction in size of the heterogeneously enhancing solid mass lesion (Fig. 1C). Presently the patient is asymptomatic. Patient consent was obtained for use of images in the study.
Patients with DAM are initially asymptomatic, but with progression present with feeling of fullness, pelvic pain, dysmenorrhea, swelling in the perineum, and alternation in bladder and bowel movements.1 Given the rarity of the tumor, non-specific symptoms, and diagnosis being established by histology alone, identification demands a high index of suspicion. DAM is commonly reported in the soft tissue of the pelvis and perineum. Few cases have also been reported in the scrotum and spermatic cord.2 On computed tomography, DAM appears as a homogenous hypodense mass. Magnetic resonance imaging of the lesion is hypointense and hyperintense on T1-weighted and T2-weighted images, respectively. Contrast enhancement is seen as a distinct wanning, eddy currents pattern, which has been hypothesized to be secondary to the presence of abundant water content and myxoid matrix of the tumor.2 On gross, the tumor is poorly circumscribed with a size range of 1–60 cm. The cut surface is bulky having a glistening mucoid springy appearance with foci of congestion and hemorrhage.4 Histology shows haphazardly interspersed blood vessels having variable muscular walls amidst a myxoid stroma. Also seen are intervening fine collagen fibers and perivascular extravasated erythrocytes. The tumor cells are stellate to spindle cells having ill-defined cytoplasmic membranes with oval nuclei and fine dispersed chromatin. Mitotic figures are seldom seen; however, the margins are always infiltrative.2 The tumor cells show a characteristic immunophenotype with positivity for vimentin, desmin, smooth muscle actin, estrogen receptor, and progesterone receptor.1,2 DAM have translocations involving the high Mobility Group A gene in chromosome 12q13-15. The differentials considered include: myxoid lipomatous tumors, superficial angiomyxoma, angiomyofibroblastoma, and myxoid leiomyoma.1,2,4 Myxoid lipomatous tumor—Myxoid lipoma and myxoid liposarcoma have abundant adipocytes, characteristic chicken wire patterned vessels, and immunoreactivity for S100p. Superficial angiomyxoma arise in the dermal or subcutaneous plane with a lobular pattern and lack expression for estrogen and progesterone receptor. Angiomyofibroblastoma has characteristic hypocellular and hypercellular areas of plump epithelioid tumor cells. Myxoid leiomyoma shows areas of transition from characteristic smooth muscle cells to myxoid areas.2,4,5 Treatment of choice is surgery to debulk the tissue, as negative margins are difficult to achieve as the tumor is infiltrative. The residual or large tumors can also be tackled using tumor embolization or radiation therapy.3,6 In pre-menopausal patients, tumors respond well to GnRH agonists as a medical management in an adjuvant setting to achieve complete radiographic resolution.3 The DAM shows a recurrence rate of 25%–47%, which may require a repeat surgery. However, the prognosis of this tumor is considered good with only isolated case reports of metastases.1,2
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Disclosure of competing interest
The authors have none to declare.
Acknowledgements
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References
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