|Year : 2015 | Volume
| Issue : 3 | Page : 645
Isolated angiomyolipoma of vulva: A case report of an uncommon tumor at an uncommon site
Monika Garg1, Amrita Duhan2, Smridhi Bindroo1, Jasveen Kaur1, NC Mahajan1
1 Department of Pathology, MM Institute of Medical Science and Research, Mullana, Ambala, India
2 Department of Pathology, BPS GMC for Women, Khanpur Kalan, Sonepat, Haryana, India
|Date of Web Publication||9-Oct-2015|
H No: 143, Sector 4, Rohtak - 124 001, Haryana
Source of Support: None, Conflict of Interest: None
Extra renal angiomyolipoma is an exceedingly rare entity. This is usually not associated with tuberous sclerosis as it has no human melanoma black 45 immune reactive cells although it shares the terminology with renal angiomyolipoma. The histological features are characterized by admixture of blood vessels, smooth muscles, and mature adipose tissues in variable proportion. Surgical excision is considered curative. We report a case of isolated vulval angiomyolipoma in a 45-year-old female which clinically and radiologically presented as lipoma like lesion. Our case of isolated vulval angiomyolipoma is the first reported case in the literature.
Keywords: Angiomyolipoma, isolated, vulva
|How to cite this article:|
Garg M, Duhan A, Bindroo S, Kaur J, Mahajan N C. Isolated angiomyolipoma of vulva: A case report of an uncommon tumor at an uncommon site. J Can Res Ther 2015;11:645
|How to cite this URL:|
Garg M, Duhan A, Bindroo S, Kaur J, Mahajan N C. Isolated angiomyolipoma of vulva: A case report of an uncommon tumor at an uncommon site. J Can Res Ther [serial online] 2015 [cited 2019 Nov 18];11:645. Available from: http://www.cancerjournal.net/text.asp?2015/11/3/645/147385
| > Introduction|| |
Angiomyolipoma is a rare tumor first described by Morgan in 1951 in kidney.  It is a rare, benign tumor composed of a variable amount of adipose tissue, spindle and epithelioid smooth muscle-like cells, and abnormal thick-walled blood vessels most commonly affecting kidney.  Extra renal angiomyolipoma is uncommonly encountered with liver being the most frequently involved organ. Some cases have also been reported in other sites such as mediastinum, heart, spermatic cord, fallopian tube, oral cavity, penis, salivary glands, and skin.  However, despite extensive English-language literature search, no case of vulval angiomyolipoma was found to be reported. Hence, we present this rare case along with discussion of its histopathological and immunohistochemical features.
| > Case report|| |
A 45-year-old lady came with the complaint of painless swelling in the perineal region since 2 months. The swelling was insidious and progressive. She was gravid two, para two and had attained menopause 2 years back with previous cycles being regular with normal flow. The local examination revealed an irregular swelling, soft to firm in consistency, present on the right side of labia majora measuring 4 cm × 3 cm × 2 cm. Overlying skin was normal. Per-speculum examination revealed healthy cervix and vagina. On per-vaginal examination, uterus was retroverted with bilateral fornices free. All biochemical investigations were within normal limits. On ultrasonography-the vulval swelling revealed a hyperechoic lesion with lobulated margins measuring 3.2 cm × 2.5 cm × 1.6 cm. Liver, spleen, gall bladder, left kidney, and uterus were normal. Right kidney showed a small concretion in the upper calyx. Fine-needle aspiration of the swelling yielded blood mixed fatty aspirate and the lesion was reported as a lipomatous lesion. Receiving the preliminary diagnosis of lipoma, the patient underwent complete excision, and the specimen was sent for histopathological examination.
Grossly, specimen was received in multiple pieces, collectively measuring 3 cm × 2.4 cm × 0.5 cm. Microscopically, sections showed a well-demarcated lesion surrounded by an incomplete capsule. The tissue was composed of an admixture of blood vessels, mature adipose tissue, and smooth muscle fibers. Aggregates of lymphocytes were noted focally. Final diagnosis of angiomyolipoma of vulva was made [Figure 1]. The patient had no signs of tuberous sclerosis or any evidence of angiomyolipoma of the kidney. The patient is currently on follow-up and shows no evidence of recurrence for a year and a half.
|Figure 1: (a) Angiomyolipoma with thin-walled vessels and mature adipose tissue with perivascular lymphocytic infiltrate (H and E, ×40); (b) intimate mixture of smooth muscles, blood vessels and mature fat cells (H and E, ×100); (c) predominant mature fatty tissue (H and E, ×200); (d) focal stratified squamous epithelial lining of vulva (H and E, ×400)|
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| > Discussion|| |
Angiomyolipoma is rare, benign mesenchymal tumor of mixed mesenchymal origin predominantly occurring in kidneys. It was previously considered to be a hamartoma or choristoma; but now is known to be neoplastic. It occurs most frequently in women with median age being 46 years.  Most of the cases are asymptomatic and therefore detected either incidentally or in biopsies performed for another reason. Two types of angiomyolipoma have been described: Isolated angiomyolipoma and angiomyolipoma associated with tuberous sclerosis.  Isolated angiomyolipoma occurs sporadically and accounts for 80% of cases while that associated with tuberous sclerosis accounts for 20% of cases.  Tuberous sclerosis complex (TSC) is a genetic disorder characterized by the growth of dysgenic lesions in multiple organs including the brain, skin, kidney, heart, lungs, and retina. TSC arises from inactivating mutations of either TSC1 (chromosome locus 9q34.3) or TSC2 (16p13.3), which encode hamartin and tuberin, respectively, which are believed to function as tumor suppressors. 
Grossly, angiomyolipoma appears as a well-delineated brownish yellow mass which may or may not be encapsulated, and its size may range from few cm to 20 cm. In our patient, it was approximately 3.0 cm in diameter. Hemorrhage, focal necrosis, cystic degeneration, and focal dystrophic calcification are frequent, and there variation may present difficulty in differentiating it from a malignant tumor. 
Microscopically, it is composed of blood vessels, smooth muscles, mature adipose tissue with a variable proportion of each component. One of its components may be less, hence can wrongly be diagnosed as angiolipoma, vascular leiomyoma or myolipoma especially when sampling is inadequate. In difficult cases with either marked atypia or scant adipose tissue, immunohistochemical studies may be helpful. Most distinctive component of this tumor is human melanoma black 45 (HMB-45) positive smooth muscle component. 
Most of the angiomyolipoma express both smooth muscle markers (smooth muscle actin-100% positivity) and melanocytic markers (HMB-45-80% positivity). This unique immunohistochemical reactivity has served as a very useful tool in differentiating angiomyolipoma from other tumors. Pea et al. have proposed that perivascular epithelioid cells often arranged around vascular spaces, co-expressing smooth muscle and melanocytic markers are the common progenitor.  In contrast to findings of Pea et al., a study by Chan et al. showed that HMB-45 reactivity occurs not only in epithelioid cells but also frequently in spindle cells.  Extra renal angiomyolipoma despite the histological similarity differs in several ways from renal angiomyolipoma. Extra renal angiomyolipoma preferably occurs in old age, is small in size and well circumscribed, is HMB negative and can be easily resected. However, renal angiomyolipoma can reach much larger size and are usually invasive and can recur. Those associated with tuberous sclerosis are positive for HMB-45. Lymphocytic aggregates in the tumor are uncommon in renal angiomyolipoma but is frequently encountered in extrarenal angiomyolipoma (including the present case). 
Fine-needle aspiration cytology has been shown to be an effective way to avoid unnecessary radical therapy in selected cases if one obtains a mixture of adipose tissue, smooth muscle bundles, and blood vessels. In our case we received plenty of adipose tissue only, which rendered the incorrect diagnosis of lipoma.
Radiologically, the lesion appears as a well-defined density surrounded by a narrow zone of radiolucency and often gives the appearance of being encapsulated. The diagnosis of angiomyolipoma is based on the combination of clinical history, imaging tests, and histological examination.
In the present case, angiomyolipoma presented as a primary lesion in the vulva without any evidence of tuberous sclerosis or renal involvement. The morphology was typical with no atypical or bizarre cells, and there was no evidence of epithelioid types of smooth muscle cells. To the best of our knowledge, this is the first case of primary angiomyolipoma of vulva with typical histological features.
Definite treatment is complete excision of mass which gives excellent results without any recurrence up to date.
| > Conclusion|| |
In conclusion, although rare, angiomyolipoma should be considered in the differential diagnosis of vulval tumors. Research is needed on a large series of cases in order to be able to understand the histogenesis, nature, and malignant potential of angiomyolipoma cases.
| > References|| |
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