Recurrent transperineal aggressive angiomyxoma: a case report

Background: aggressive angiomyxoma is a rare disease that may cause misdiagnosed in the clinical work and the characteristic of this disease is low potential malignancy. This case shows a recurrent case of aggressive angiomyxoma 7 years after the surgery which was mistakenly diagnosed at that time. Case presentation: the patient presented a large mass in the right labium majus without any pain. This mass was recurrent 7 years after she received a surgery about the mass occurred at the same place which was diagnosed as vulvar angiomyofibroblastoma. She took the ultrasound scan and MRI scan and underwent the surgery again. This mass was excision completely. At this time, pathologist checked the HE stained slides and immunohistochemistry staining slides, then come the the conclusion that this mass was aggressive angiomyxoma. We rechecked the pathological slides 7 years ago and found out it was misdiagnosed at that time. Conclusions: Aggressive angiomyxoma is a rare tumor. This case presents a rare disease that may be misdiagnosed as other benign vulvar disease even after the surgery which get pathologic evidence. So we need to know more about this disease.

pain. This mass was recurrent 7 years after she received a surgery about the mass occurred at the same place which was diagnosed as vulvar angiomyofibroblastoma. She took the ultrasound scan and MRI scan and underwent the surgery again. This mass was excision completely. At this time, pathologist checked the HE stained slides and immunohistochemistry staining slides, then come the the conclusion that this mass was aggressive angiomyxoma. We rechecked the pathological slides 7 years ago and found out it was misdiagnosed at that time.
Conclusions: Aggressive angiomyxoma is a rare tumor. This case presents a rare disease that may be misdiagnosed as other benign vulvar disease even after the surgery which get pathologic evidence. So we need to know more about this disease.

Background
Aggressive angiomyxoma is a rare stromal disease that most frequently occurs in the premenopausal women, especially between second and forth decade, which is usually arise from mesenchymal tissue and presents low potential malignancy. This tumor is often misdiagnosed as Bartholin's cyst, angiomyofibroblastoma or hernia because of its nonspecific clinical and radiological aspects [1]. In this case, we'll describe a case about a female patient who was mistakenly diagnosed as angiomyofibroblastoma after initial surgery and recurrent 7 years later with the correct diagnosis at the same time.

Case presentation
A 38-year-old female came to the outpatient department of our hospital, presented with a progressive enlargement asymptomatic mass in the right labium majus with a duration of 1 year growth [ Figure 1]. The patient complained that the nontender mass was recurrent, with a history of mass excision she underwent at the same site as the primary lesion 7 years ago. imaging showed hypointense while T2-weighted images showed high signal intensity compared to muscle at the same time. There was mild enhancement after gadolinium injection. No obvious enlarged lymph node was observed in pelvic. The MRI diagnose was right perineum mass, intended to consider as benign tumor like angiomyolipoma or hemangioma。 On palpation, the physical examination showed a mass on the right labia majora which was about 8*4cm in size, with obvious pigmentation, soft texture and no tenderness ( Figure.2).
Hence, a surgical operation was performed, which in the proceed, we could find the upper edge of the mass is the pubic symphysis, the right edge is the pubic arch, the left edge is the right vaginal wall, partly protrudes toward the vagina, and the lower edge is the level of the sacral ligament. The mass suffered complete excision and on macroscopic view, the sectioned surfaces were soft accompanied by edema and mucoid degeneration change.
The gross appearance of the tumor was large, which was about 8 cm in maximum diameter.
Microscopic observation revealed that the tumor volume was large, unclear boarder and growed deeper and infiltrated into surrounding fat tissue. There was even and consistent mucus inside the tumor with low cell density and mild morphology. The cells were little atypical and no mitosis phase. A lot of vessels could be found in the background of mucous which the vessel walls varies in diameter and thick-walled vessels and hyaline degenerated vessels could be seen. The immunohistochemistry staining results of the mass were positive for smooth muscle actin, desmin, vimentin, CD31 and CD34, meanwhile negative for S-100.

Discussion and conclusions
Aggressive angiomoyxma is uncommon benign mesenchymal tumor with a predilection for perineum, which characteristics are a high risk of relapse after resection [2] and usually have a large size. It was first reported in 1983 by Steeper and Rosai [3]. It looks morphologically  B C similar as angiomyofibroblastoma which both grow at a very slow rate that hence patients will be asymptomatic for a long time before they are conscious of the mass [4].
Usually, histopathologic examination of aggressive angiomyxoma revealed numerous thick-walled blood vessels in a hypocellular myxoid stroma, the irregular boundary and abundant mucous matrix with hyaline change in the vessels' wall. Immunohistochemically, the stromal cells showed expression of desmin, smooth muscle actin, vimentin and CD34 in which atypical vessels cound be found in. In pathology it needs to identify with angiomyofibroblastoma which is rare vascular soft tissue neoplasma in vulva.
Angiomyofibroblastoma is morphyologically familiar to aggressive angiomyxoma as they share many features such as painless and slow-growing mass. But histopathologically it displays superficial vascular mucinous, clear boundary, more smooth muscle components in stromal matrix and presents more pathological thin-walled blood vessels [5]. It's usually negative for desmin, smooth muscle actin, vimentin and CD34 as the same time.
Considering of its high local recurrence and characteristic of aggressive, a complete surgical excision is very important [6], which patients will get benefit from it. Tumor-free margin surgical excision is considered as a usual way to get the treatment. But unfortunately, even patients get the complete resection of the mass, it still has the possibility to recurrent [7] and it usually occur at the same site as the primary one [8]. So a long-term follow-up is very necessary.
As to this patient, she was misdiagnosed 7 years ago after her first surgery. The mass she got excision was diagnosed as angiomyofibroblastoma as we reviewed the pathological slides this time in which revealed thick wall vessels and vascular proliferation can be seen in the mucoid stroma, which showed typically aggressive angiomyxoma. But at that time, pathologist was lack of experience and couldn't tell the difference between the two disease.
It was until 7 years after the patient got the correct diagnose.
The patient has been under follow-up for 2 years now, and remains asymptomatic and with no radiological evidence of recurrence.
Aggressive angiomyxoma is a rare tumor and surgical excision is the first option to cure the disease [9]. Pathologic is the gold standard for diagnose. This case presents a rare disease that may be misdiagnosed as other benign vulvar disease even after the surgery which get pathologic evidence. Hence experienced pathology doctors are very important. But we can still get some clues by review medical history and investigate the imaging features.

Ethics approval and consent to participate
The present study was approved the Institutional Review Board of The Second Affiliated Hospital of Zhejiang University School of Medicine.

Consent for publication
Consent was obtained from the patient Availability of data and material The datasets supporting the conclusions of this article are included within the article and its Additional files.

Competing interests
The authors declare that they have no competing interests.

Funding
This work has no funding support.  Changes of body weights in the rats exposed to NaDCC. Males(A) and Females(B) of the main groups, Males(C) of the recovery gr oups. Signi cantly different from control by Dunnett LSD test : *p<0.05, **p< Changes of feed intake in the rats exposed to NaDCC. Males(A) and Females(B) in the main groups, Males(C) in the recovery groups. Signi cantly different from control by Dunnett LSD test: *p<0.05.

Figure 4
Total cell counts(A) and differential cell percentage(B) of total cells from bronchoalveolar lavage uid (BALF) after NaDCC exposure. The values are expressed as mean ± SD (n = 5 males per group).).  Histopathology of the nasal cavity of male rats exposed to NaDCC, A), B) No abnormal lesion was observed In the control group, C), D), Degeneration (arrow) of transitional epithelium was observed in the 20 mg/m 3 exposed group. A), C) X50, B), D) X400, respectively, HE Figure 7 Histopathology of the larynx of male rats exposed to NaDCC, A), B) No abnormal lesion was observed in the control group, C), D), In ammation (arrow) of epithelium was observed in the 20 mg/m 3 exposed group. A), C) X50, B), D) X400, respectively, HE

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