Hepatic falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors
Wang et al. BMC Cancer
Hepatic falciform ligament clear cell myomelanocytic tumor: A case report and a comprehensive review of the literature on perivascular epithelioid cell tumors
Zu-Sen Wang 0
Lin Xu 0
Lin Ma 2
Meng-Qi Song 0
Li-Qun Wu 0
Xuan Zhou 1
0 Department of Hepatobiliary Surgery, Affiliated Hospital of Qingdao University , Qingdao, Shandong 266003 , China
1 Department of Pathology, Affiliated Hospital of Qingdao University , Qingdao, Shandong 266003 , China
2 Department of General Surgery, Qingdao Eighth People's Hospital , Qingdao, Shandong 266003 , China
Background: The objective of the study was to explore the clinical expression, radiological and pathological features, differential diagnosis, and biological behavior of a clear cell myomelanocytic tumor. In a case involving a clear cell myomelanocytic tumor located in the hepatic falciform ligament, we evaluated clinical expression, radiological characteristics, histopathology, immunohistochemistry, and biological behavior; we also reviewed the relevant literature. Case presentation: Clear cell myomelanocytic tumor is a benign soft-tissue neoplasm that often occurs in women, and is expressed as a painless mass. The falciform ligament is its most frequent site of occurrence. The imaging characteristics of this lesion were uneven enhancement in the arterial phase, continuing to strengthen in the venous phase, and equal density in the balance phase. Histological and immunohistochemical analysis revealed the main transparent epithelioid cells and smooth muscle spindle cells to be HMB-45(+), smooth muscle actin(+), and melan-A (+). Conclusion: Hepatic vascular epithelioid cell tumors are very rare mesenchymal neoplasms. Few studies have investigated this tumor in the hepatic falciform ligament; consequently, its diagnosis and the selection of an appropriate treatment and follow-up protocol are challenging. Treatment outcome remains unpredictable. Therefore, clear cell myomelanocytic tumor should be viewed as a tumor with uncertain malignant potential requiring long-term follow-up.
CCMMT; Diagnosis; Immunohistochemistry; PEComa
Background
Perivascular epithelioid cell (PEComa) tumor has
recently been cytopathologically defined. Histological and
immunohistochemical analysis indicate that it has the
obvious characteristics of perivascular epithelioid cells
(PECs) [
1, 2
]. A type of tumor with hyaline cells that has
the characteristics and similarity to a neoplasm with
perivascular epithelioid cell differentiation is determined
as follows according to the World Health Organization
(2002) soft-tissue tumor classification: a neoplasm with
perivascular epithelioid cell differentiation, including
hepatic falciform ligament clear cell myomelanocytic
tumors [3]. Because soft-tissue clear cell myomelanocytic
tumor (CCMMT) is a newly identified tumor type, there
have been very few previous studies. This tumor usually
involves the uterus, followed by the sickle ligament and
gut. There have been only two reported cases of
CCMMT in the liver [
4
]; thus, the diagnosis and
differential biological behavior of this neoplasm require
further study. The present report involves the evaluation of
a case of CCMMT and a review of the relevant
literature.
Case presentation
A 29-year-old woman was admitted to our hospital in
July 2014 with liver cancer rupture after intervention
over a period of 1 month. She had a treatment history
involving L-carnitine drugs proceeded by cesarean
section (4 months ago), and no history of hepatitis and
hepatocirrhosis. A physical examination revealed the
following: the right side of the abdomen was slightly
bloated; there was a 10-cm surgical scar on the
hypogastrium, and a palpable 5 × 6 cm mass was present in the
right upper abdomen; the mass was hard, smooth, and
had good texture; and there was no pain when the mass
was pressed. Laboratory examination revealed routine
hepatic and renal function, and normal levels of serum
electrolytes and alpha fetoprotein.
Ultrasound examination of the digestive system
demonstrated the following: a heterogeneous
hyperechoic mass (15.5 × 9.6 × 14.2 cm) located in the right
hepatic lobe; an irregular anechoic area in the mass; a
clear boundary; and no obvious blood flow signal in
the mass examined using color Doppler flow imaging
(Fig. 1). A plain abdominal computed tomography
(CT) scan showed a huge abdominal mass below the
right segment of the anterior hepatic lobe, an uneven
internal density, and high and low mixed density
(Fig. 2). A dynamic enhanced CT scan of the upper
abdomen demonstrated the following: a mixed
highand low-density mass shadow in the right anterior
hepatic lobe below segment S5; a clear boundary; a
neat outline; significant uneven enhancement;
internally, a large area of low-density non-enhanced
shadow; multiple enlargement of the surrounding
vessels; and a low-density coated edge.
Hepatic arterial enhancement was uneven, but the
venous and balance periods strengthened mo (...truncated)