Broad Ligament Lipoleiomyoma Masses Two curious cases masquerading as ovarian carcinomas

Lipoleiomyomas are an extremely rare form of uterine leiomyoma; moreover, the occurrence of this type of tumour on the broad ligament is even rarer. We report two cases of broad ligament lipoleiomyomas in 15- and 38-year-old female patients who presented to the Lok Nayak Jai Prakash Hospital in New Delhi, India, between 2016 and 2017. In both cases, the preoperative diagnosis was of a solid ovarian malignancy. Most broad ligament tumours are mistaken for ovarian masses as they are difficult to diagnose radiologically.

An exploratory laparotomy revealed a tumour of 26 cm in size protruding out of the abdominal cavity.There was no connection between the tumour and the left ovary; instead, it was attached to the left lateral aspect of the uterus.Upon gross examination, the tumour was smooth, homogenous and greyish-white [Figure 2A].The lump was excised and a specimen was sent for frozen section analysis.Microscopically, interlacing bundles of benign spindle-shaped cells with intermingled fat cells were observed [Figure 2B].The randomly distributed fat cells were mature and there was no evidence of lipoblasts, mitosis, necrosis or angiomatosis.There was no cytological atypia in the spindle cells or adipocytes.On immunohistochemistry, the tumour cells were positive for smooth muscle actin (SMA) but negative for human melanoma black (HMB)-45.The patient was diagnosed with a broad ligament lipoleiomyoma and subsequently underwent conservative surgery to fully excise the mass.One week later, her thyroid hormone profile had returned to normal.At a six-month follow-up appointment, the patient appeared to be healthy with no evidence of disease recurrence.

Case Two
A 38-year old gravida 2, para 2 female presented to LNJPH in 2017 with an uncomfortable abdominal mass which had been increasing in size over the previous year.She had never experienced any menstrual irregularities and there were no significant events in her past medical or surgical history.A physical examination revealed a left-sided abdominopelvic mass without evidence of lymphadenopathy or organomegaly.Routine tests, including serum tumour markers, were within normal limits.An MRI scan showed a large left-sided heterogeneously enhancing abdominopelvic mass with   Surekha Yadav, Barkha Maheswari, Nishant Sagar, Varuna Mallya, Nita Khurana and Sangeeta Gupta Case Report | e479 adenopathy) and malignant (malignant teratoma and liposarcoma) lesions. 6][7][8][9][10] To the best of the authors' knowledge, the 15-year-old girl described in the first case of this report appears to be the youngest known patient to develop a broad ligament lipoleiomyoma.
Among lipoleiomyomas, distribution of the adipocytic component can vary widely from being uniformly spread throughout the tumour to a more focal concentration in small areas; as such, there is no defined cut-off percentage of adipocytes to confirm the diagnosis.In terms of appearance, those tumours containing few microscopic foci of adipocytes tend to resemble regular leiomyomas with large amounts of adipocytic components usually indicated by a yellowish appearance and a lobulated cut surface. 2adiologically, the diagnosis of a lipoleiomyoma is challenging as these masses often resemble an ovarian tumour. 9,11The lobules of mature fat in a lipoleiomyoma intermingle with wisps of smooth muscles, which can be misleading and resemble the atypical hyperchromatic spindle cells of a well-differentiated liposarcoma.Therefore, the accurate diagnosis of this entity depends on the correct identification of the benign smooth muscle cells. 7veral hypotheses have been proposed to explain the origin of uterine lipoleiomyomas, including lipomatous metaplasia, metaplasia in the pluripotent lobulated margins measuring 30 x 25 x 15 cm.The left adnexa was not visualised separately.A provisional diagnosis of a malignant ovarian tumour was made.Accordingly, the patient underwent a total abdominal hysterectomy with a bilateral salpingo-oophorectomy.
During the surgery, the tumour was observed to be separate from the left ovary and attached to the left broad ligament.There was no evidence of lymphadenopathy and all other organs appeared to be healthy.On gross examination, the tumour measured 30 cm in its greatest dimension and was homogenous and greyish-coloured, with focal yellow areas [Figure 3A].Microscopically, the tumour showed features of a benign spindle cell lesion [Figure 3B].Immunohistochemistry was once again positive for SMA but negative for HMB-45.The final diagnosis was of a broad ligament lipoleiomyoma.The patient appeared healthy at a three-month follow-up appointment.

Discussion
Lipomatous tumours of the uterus are divided into three groups: pure lipomas composed of mature adipose tissue, lipoleiomyomas composed of a mixture of smooth muscle cells and mature adipose tissue and malignant liposarcomas. 2The differential diagnosis of pelvic lipoleiomyomas includes both benign (i.e.teratomas, benign pelvic lipomas, non-teratomatous lipomatous ovarian tumours and lipoblastic lymph- mesenchymal cells or the perivascular extension of fat along the blood vessels with a complex histogenesis according to immunohistochemical studies. 2,7,11Renal angiomyolipoma-like vascular proliferation has also been reported in a case of lipoleiomyoma. 5 However, neither of the present cases exhibited cellular atypia nor vascular proliferation; furthermore, the tumour cells were immunonegative for HMB-45.1][12] The cause of metabolic disturbances among older patients with lipoleiomyomas is generally assumed to be due to altered lipid metabolism; however, the precise reason for this alteration is still unknown. 10

Conclusion
The diagnosis of a lipoleiomyoma can be challenging as their appearance upon imaging resembles that of a liposarcoma.Due to their solid nature, lipoleiomyomas may necessitate surgical intervention to relieve associated symptoms and rule out ovarian malignancy.Patients may also have underlying hormonal disturbances which normalise after surgery; as a result, regular follow-up appointments should be undertaken.

Figure 2 :
Figure 2: A: Gross image of an excised lesion from a 15-year-old female, showing a well-circumscribed greyish soft mass with a smooth external surface.B: Haematoxylin and eosin stain at x400 magnification showing mature smooth muscle cells and intermingled mature adipose tissue (arrow).

Figure 1 :
Figure 1: Magnetic resonance imaging scan of a 15-year-old female showing a heterogeneously enhancing solid-cystic pelvic mass (arrow).

Figure 3 :
Figure 3: A: Gross photograph of an excised lesion from a 38-year old female, showing a homogenous greyish mass with focal areas of central fat (arrow).B: Haematoxylin and eosin stain at x400 magnification showing interlacing bundles of benign spindle-shaped cells with intermingled fat cells (arrow).