A Review of the Literature on Extrarenal Retroperitoneal Angiomyolipoma

Abstract

Background. Extrarenal retroperitoneal angiomyolipomas are rare. Aim. To review the literature. Results. Angiomyolipomas, previously classified as hamartomas, are now classified as benign tumours. Thirty cases of primary retroperitoneal angiomyolipomas have been reported. Diagnosis of the disease upon is based radiological and pathological findings of triphasic features of (a) fat and (b) blood vessels and myoid tissue. Immunohistochemistry tends to be positive for HMB45, MART1, HHF35, calponin, NKI-C3, and CD117. The lesion is common in women. Treatment options have included the following: (a) radical surgical excision of the lesion with renal sparing surgery or radical nephrectomy in cases where malignant tumours could not be excluded and (b) selective embolization of the lesion alone or prior to surgical excision. One case of retroperitoneal angiomyolipoma was reported in a patient 15 years after undergoing radical nephrectomy for angiomyolipoma of kidney and two cases of distant metastases of angiomyolipoma have been reported following radical resection of the tumour. Conclusions. With the report of two cases of metastases ensuing surgical resection of the primary lesions there is need for academic pathologists to debate and review angiomyolipomas to decide whether to reclassify angiomyolipomas as slow-growing malignant tumours or whether the reported cases of metastases were de novo tumours or metastatic lesions.

Retroperitoneal extrarenal angiomyolipoma at the surgical bed 8 years after a renal angiomyolipoma nephrectomy: A case report and review of literature

“…It has triphasic morphology on histology that includes mature adipose tissue, thick-walled blood vessels, and perivascular spindle cells. [ 3 4 5 6 ] They show immunoreactivity to smooth muscle actin, HMB-45, and melanocytic marker Melan-A. [ 7 ] AMLs can occur in inherited forms in association with tuberous sclerosis (10%–20%); however, the sporadic form is the most common (80%–90%).…”

Spermatic cord angiomyolipoma misdiagnosed as inguinoscrotal hernia

“…In AML immunohistochemical studies show positive staining for various markers such as MART1/Melan-A, muscle-specific actin (HHF35), HBM45, calponin, NKI-C3. Also, AML tend to be negative for renin and keratin [6,8]. In our case, histopathological and immunohistochemical examination revealed typical AML.…”

“…Extrarenal retroperitoneal AML may present in a variety of ways, such as incidental radiological finding, abdominal pain, loin and back pain, felling of fullness in the abdomen, diffuse pain and bleeding, hematuria, vomiting, constipation, weight loss, abdominal mass [6]. Pain in the right groin, high fever, and a local finding indicative of incarcerated inguinoscrotal hernia were present in our patient.…”

“…These tumors show phenotypic (smooth muscle, epithelioid, and lipid-rich histology), and immunohistochemical coexpression of myogenic (smooth muscle actin) and melanocytic (HMB-45, melan A, microphthalmia transcription factor, tyrosinase) modulation. In other words, pathohistological findings of AML typically tend to have triphasic features: myoid spindle cells, islands of fat tissue, and dysmorphic blood vessels that have thick walls and do not have elastic lamina [6,7]. In AML immunohistochemical studies show positive staining for various markers such as MART1/Melan-A, muscle-specific actin (HHF35), HBM45, calponin, NKI-C3.…”

“…According to Minja et al [3], CT scan is the commonest used radiologic technique in the investigation of AML. Also, brain CT is recommended in patients with AMS, because about 40% of them have CT features of tuberous sclerosis [6]. High proportion of fat content, which is [3] found in the majority of AML, produces a characteristic pattern on CT scan.…”