Multiple hepatic angiomyolipomas with a solitary omental angiomyolipoma

Trans Arterial Embolization of Spontaneous Intra-Abdominal Haemorrhage from Omental Lipoma

We describe 3 cases of omental lipoma of whom 2 presented with symptomatic haemorrhage. Notably the haemorrhage in the 2 reported cases was from foregut arteries. Thorough knowledge of anatomy and embryology is critical in identifying the source of haemorrhage and differentiating this condition from other common causes of mesenteric haemorrhage. To the best of our knowledge, this is the first case series reporting this uncommon cause for abdominal haemorrhage. The successful management of this condition using superselective embolization is discussed. Clinicians need to exercise diligence and caution in omental lipomas presenting with spontaneous haemorrhage and this notion is exemplified in our reported cases.

A rare case of perivascular epithelioid cell tumor (PEComa) of the greater omentum

Background

A tumor composed exclusively or predominantly of human melanin black 45 (HMB45)-positive epithelioid cells is called a perivascular epithelioid cell tumor (PEComa). We report a very rare case of a PEComa of the greater omentum.

Case presentation

MRI conducted to examine the orthopedic disease of the patients, a 49-year-old Japanese woman, also identified a tumor in her pelvis. A CT scan revealed a tumor mass on the right side of the pelvic floor and clear nutrient vessels originating from the splenic and celiac arteries. An omental primary tumor or accessory spleen was thus suspected, and tumor resection was performed. The tumor was a light brown solid tumor with a smooth margin, measuring 5.2 × 3.8 × 3.5 cm. Histopathologically, the tumor was composed mainly of spindle and epithelioid cells, and large and small blood vessel formation was observed. In the immunohistochemical staining, tumor cells were positive for human melanin black 45 (HMB-45) and Melan-A and partially positive for alpha-smooth muscle actin. The final diagnosis was PEComa of the greater omentum.

Conclusions

Although omental PEComa is very rare, it should be considered as a differential disease of an omental primary tumor.

Liver angiomyolipomas: a clinical, radiologic, and pathologic analysis of 22 patients from a single center

BACKGROUND

Liver angiomyolipomas (AML) are mesenchymal neoplasms with an uncertain clinical behavior. The spectrum of presentation, imaging and histologic features, and outcomes were analyzed in all patients treated at Memorial Sloan-Kettering Cancer Center.

METHODS

Demographics, disease, pathologic, treatment, and outcome-related variables for consecutive patients were reviewed retrospectively. All imaging studies obtained at presentation were reexamined, categorized, and compared using Fisher and Wilcoxon tests.

RESULTS

Between 1989 and 2010, 238 patients with AML were seen and 22 (9.3%) had liver involvement (exclusive = 17; combined with kidney = 5). The median age was 53 years; 18 were females, and 15 had symptoms. AML was not suspected at initial presentation in any patient. Fat-containing neoplasms on imaging were larger (P = .03), with more heterogeneous enhancement compared with fat-poor neoplasms (P = .001), but none of the imaging/histologic features correlated with outcome. Thirteen patients underwent resection (R0 = 9), 4 were observed, 2 received chemotherapy, 2 embolization, and 1 embolization plus intra-arterial chemotherapy. Two patients treated with R0-resection recurred and 2 treated with chemotherapy progressed, but no patient died of AML-related causes. At a median follow-up of 36 months, 7 patients were free of disease, 13 were alive with disease, 1 died of an unrelated cause, and another was lost to follow-up.

CONCLUSION

AMLs are rare neoplasms with an indolent course in most patients. Subtypes based on fat content are recognized, but clinical behavior does not seem to be different. Recurrence after resection is not associated with disease-related mortality. Resection may be unnecessary in selected asymptomatic patients if the diagnosis can be established definitively.

Diagnosis and treatment of hepatic angiomyolipoma

BACKGROUND AND OBJECTIVE

Hepatic angiomyolipoma is more frequently encountered in clinical practice, its diagnosis is difficult, its treatment remains controversial. We review a single-center experience in the treatment of hepatic angiomyolipoma.

METHOD

The clinical data of 79 patients with hepatic angiomyolipoma treated at the authors' institute between January 1992 and December 2006 were retrospectively reviewed.

RESULTS

During a period of 15 years, a total of 79 patients with hepatic angiomyolipoma underwent liver resection at our hospital. There are 58 women and 21 men. The tumor size varied from 1 to 25 cm in diameter (6.1 ± 4.08). Fifty-four patients (68%) were asymptomatic. Accurate preoperative diagnosis was made in 41 patients (52%). Tumors less than 6 cm in size were more frequently misdiagnosed. Spontaneous rupture occurred in one patient. One patient had tumor recurrence 6 years after the surgery, and died of the disease 1 year later. Symptom relief was achieved in 92% of the symptomatic patients. Median survival was 90 months (90.12 ± 30.84).

CONCLUSIONS

Hepatic angiomyolipoma poses a diagnostic challenge clinically and radiologically. Surgical resection is a safe and effective treatment option. It is important to realize the potential of malignant transformation and risk of rupture as life-threatening complications.

Hepatic angiomyolipoma: a retrospective study of 25 cases

PURPOSE

We report our experience of diagnosing and treating hepatic angiomyolipoma (HAML), a rare benign mesenchymal tumor.

METHODS

We analyzed retrospectively the clinicopathologic, radiological, and operative data of 25 patients who underwent surgery for HAML at our institute between November 2001 and May 2006.

RESULTS

Most patients (20/25) were asymptomatic and had normal liver function. Ultrasonography (US) showed a heterogeneous hyperechoic mass in 13 of 23 patients, precontrast computed tomography (CT) showed that all of 12 lesions scanned were hypodense, and magnetic resonance imaging (MRI) showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images in most (5/6) lesions. Marked enhancement in the arterial phase was seen in 10 of 12 lesions on CT scans and in 6 of 6 lesions on MRI scans. All tumors were composed of varying proportions of smooth muscle, adipose tissue, and blood vessels, and showed positive immunohistochemical staining for HMB-45. All patients underwent partial hepatectomy and there was no evidence of recurrence after a median follow-up of 43 months.

CONCLUSION

The radiological features of HAML vary according to its histological components. The definitive diagnosis of HAML is challenging and depends on the presence of HMB-45-positive myoid cells. Hepatic angiomyolipoma is treated effectively with surgery and the prognosis is good.

Neoplasms of the Perivascular Epithelioid Cell Involving the Abdomen and the Pelvis

Neoplasms of the perivascular epithelioid cell (PEComas) represent a recently described heterogeneous group of mesenchymal tumors characterized by the presence of specific histological, immunohistochemical, and ultrastructural findings. The PEComas encompass a family of neoplasms that include angiomyolipomas, clear cell sugar tumors, and lymphangioleiomyomatosis. The PEComas demonstrate a wide spectrum of clinicobiological behavior and imaging findings. Perivascular epithelioid cell, as the name implies, is a unique cell that is characterized by perivascular distribution and epithelioid morphology. Perivascular epithelioid cell consistently shows immunoreactivity to melanocytic and smooth muscle markers including HMB-45 and actin. Abdominopelvic PEComas are found at a variety of somatic and visceral locations including kidney, liver, pancreas, gastrointestinal tract, genitourinary tract, peritoneum, and retroperitoneum. A subset of patients with abdominopelvic PEComas manifests tuberous sclerosis complex. In this paper, we review the histological spectrum and discuss the imaging findings of the PEComas that involve the abdomen and pelvis.