Keywords
benign tumor - lipoma - mesenchymal tissue - soft tissue - vulva - vulvar lipoma
Introduction
Lipoma is a common benign tumor of soft tissue, and its diagnosis is confirmed by
the histopathological description of a well-circumscribed collection of mature adipose
tissue.[1] The etiology of lipoma is still to be elucidated, but it has been reported that
trauma[2] and gene rearrangement[3] may play a role in its development.
Typically found in subcutaneous fat, lipoma is frequently observed in the upper back,
the neck, and the proximal upper and lower extremities.[3] The vulva is a rare site for the development of lipomas, with few cases reported
in the literature.[4]
[5]
[6]
[7]
[8]
[9] The differential diagnosis of vulvar lipoma includes Bartholin gland cyst and abscess,
inguinal hernia, as well as several benign and malignant neoplastic conditions.[10]
Case Description
A 43–year-old woman presented to our clinic complaining of a vulvar mass that lately
had been causing her discomfort during walking and sitting. The mass was painless,
with an insidious onset and slowly progressive course over 4 years. The woman is a
house wife, p5, with no past history of clinical importance. There was no past personal
or family history of a similar condition.
Upon examination, there was a single oval mass involving the whole right labia majora
and covering the introitus ([Fig. 1]). The mass measured ∼ 15 cm in diameter, and was soft, mobile, non-tender, non-reducible,
and gave no impulse on cough. The overlying skin was mobile, but stretched over this
large mass. The mass was compressing the vagina, shifting it to the opposite side,
but it was not fixed to the vagina. There was no palpable inguinal lymph node.
Fig. 1 Vulvar swelling occupying the whole right labia majora and covering the introitus.
An ultrasonographic examination showed a homogenous echo texture with no cystic changes
or vascularity surrounded by an echogenic capsule with minimal vascularity. A magnetic
resonance imaging (MRI) scan revealed an oval soft tissue mass with a well-defined
capsule showing a homogenous high signal with suppression of a signal similar to subcutaneous
fat, and showing no diffusion restriction or postcontrast enhancement ([Fig. 2]).
Fig. 2 Magnetic resonance imaging scan showing oval soft tissue mass with well-defined capsule.
The patient underwent surgical excision; an elliptical incision on the skin was performed
to aid dissection and to remove redundant tissue for better cosmetic closure. The
mass was easily separated from the surrounding tissue, and was removed completely
from its capsule ([Fig. 3]). The histopathological examination revealed a collection of mature adipose tissue,
confirming the diagnosis of lipoma.
Fig. 3 Vulvar lipoma after surgical excision.
Discussion
Mesenchymal tissue, also referred to as soft tissue or connective tissue, is a derivative
of the mesoderm. It comprises a variety of cell types, including fibroblasts and adipocytes.
The most frequent benign mesenchymal tumor is lipoma, which is typically observed
in subcutaneous fat, but may develop in almost all body organs, including the vulva,
which is a rare site for lipoma development.
The etiology and pathogenesis of lipomas remain undetermined. Trauma, obesity and
gene rearrangement are risk factors for the development of lipomas.[2]
[3] In the current report, we could not link lipoma to any risk factor. Similarly, previous
case reports of vulvar lipoma did not find associated risk factors. Only one study[7] suggested trauma might be linked to their patient, a 17-year-old Tae Kwon Do practitioner.
Lipoma commonly develops between the fourth and sixth decades of life, but it can
be found in all age groups. Like other lipomas, vulvar lipoma has a similar pattern,
being reported in all age groups,[4]
[5]
[6]
[7]
[8]
[9] including adolescents[7]
[8] and infants.[9]
The diagnosis of lipoma is usually made through a clinical examination. It may present
as a painless mass that has a slowly progressive course and is soft, mobile and not
adherent to the overlying skin. In the current case, the clinical examination was
suggestive of lipoma, but due to the rarity of the condition, we preferred not to
rely on clinical findings alone, and decided to subject the patient to further imaging
investigations.
The ultrasound examination of a case report of vulvar lipoma showed that the appearance
of an encapsulated homogenous echogenic mass is a diagnostic criterion for lipoma.[11] An earlier study on ultrasonography of superficial lipomas revealed that the majority
of the cases had homogenous echotexture and were well-defined masses.[12] The MRI examination of lipomas usually shows high signal in weighted images, and
serves as the best imaging modality for the assessment of soft tissue.[13] In the present study, both imaging modalities were excellent in diagnosing vulvar
lipoma.
Lipomas can be managed conservatively, especially if they are small in size and asymptomatic,
for, if they grow large, they may cause discomfort and disfigurement, and may result
in psychological and social problems. Surgical excision, liposuction, laser, ultrasound
and injection of pharmaceutical agents are management options for the treatment of
lipomas.[14] Surgical excision is the treatment of choice for lipomas, with complete removal
of the capsule to prevent recurrence. In the present case, we chose surgical excision
because the mass was symptomatic, and to confirm the diagnosis of lipoma, since the
vulva is a rare site for the development of this tumor.
Conclusion
The vulva is a rare site for the development of lipomas. Ultrasonography and MRI are
the preferred diagnostic modalities for lipoma. In symptomatic cases, surgical excision
is the treatment of choice.
