Extrarenal angiomyolipomas of the perinephric space

Practical Management of Adult Ultra-Rare Primary Retroperitoneal Soft Tissue Sarcoma: A Focus on Perivascular Epithelioid Tumours and Extraosseous Ewing Sarcoma

With the exception of well-differentiated liposarcoma, dedifferentiated liposarcoma, leiomyosarcoma, solitary fibrous tumour, malignant peripheral nerve sheath tumour, and undifferentiated pleomorphic sarcoma, the majority of the ≈70 histologic subtypes of retroperitoneal sarcoma are defined as 'ultra-rare' sarcomas, with an incidence of ≤1-5/1,000,000 persons/year. For most of these ultra-rare RPS subtypes, diagnosis and treatment follows international guidelines for the management of more common RPS histologies, with en bloc surgical resection as the mainstay of curative treatment, and enrolment in clinical trials where possible. Because the treatment of RPS is heavily driven by histology, the surgeon must be familiar with specific issues related to the diagnosis and management of ultra-rare sarcoma subtypes. Expert radiological and surgeon reviews are required to differentiate similarly presenting tumours where surgery can be avoided (e.g., angiomyolipoma), or where upfront systemic therapy is indicated (e.g., extraosseous Ewing's sarcoma). Thus, the management of all retroperitoneal sarcomas should occur at a sarcoma referral centre, with a multidisciplinary team of experts dedicated to the surgical and medical management of these rare tumours. In this focused review, we highlight how diagnosis and management of the ultra-rare primary RPS histologies of malignant perivascular epithelioid cell tumour (PEComa), extraosseous Ewing sarcoma (EES), extraosseous osteosarcoma (EOS), and rhabdomyosarcoma (RMS) critically diverge from the management of more common RPS subtypes.

Aggressive angiomyxoma of renal pelvis in a horseshoe-shaped kidney: Rare tumor at an unusual site

Mesenchymal neoplasm is rare in renal pelvic region. Aggressive angiomyxomas are the neoplasms seen predominantly in female genital region. These tumors are locally aggressive with rare cases presenting with metastasis. Its occurrence in renal pelvis is extremely rare with only five cases reported in the literature. The present case is the sixth case reported in a 15-year-old girl who presented to the surgery department as a case of horseshoe kidney. The mass was excised and a diagnosis of aggressive angiomyxoma was rendered.

Surgical resection of extremely rare primary giant splenic angiomyolipoma: a case report

Background

Angiomyolipoma is a benign mesenchymal tumor that develops commonly in the kidney and rarely in other organs. The involvement of the spleen in angiomyolipoma is extremely rare, and only one such case has been reported in the English literature.

Case presentation

A 27-year-old man presented with adenoid hyperplasia and bilateral palatal tonsillar hyperplasia. During the treatment for adenoid hyperplasia, a 15-cm tumor was detected in the spleen using abdominal ultrasonography and enhanced computed tomography. Partial resection of the spleen was successfully performed. A giant tumor of approximately 13 cm with a smooth surface was observed in the upper left quadrant of the abdomen. The tumor was confirmed to be continuous with the upper spleen, and there was no invasion of the other organs. The postoperative course was good, and the patient was discharged on the 7th postoperative day. The excised specimen was a smooth, extremely soft tumor measuring 123 × 120 × 82 mm. The cleaved surface of the tumor was reddish brown, and a distressing yellow color was observed. Pathological examination revealed a proliferation of mature adipocytes and an increase in the number of blood vessels of various sizes. Furthermore, spindle-shaped cell proliferation foci were visible between the adipocytes and the surrounding blood vessels. Profuse leakage of erythrocytes from the blood vessels, hemosiderin deposition, and small round cell infiltration were also noted. Immunostaining disclosed that the spindle-shaped cells were weakly positive for smooth muscle antibody and were identified as smooth muscle cells. The adipocytes and spindle cells were negative for HMB 45, Melan A, MDM, and CDK4. However, some parts of the cells were positive for estrogen and progesterone receptors. Besides, vascular endothelial cells were positive for CD31 and CD34 and negative for CD8. Based on these findings, the patient was diagnosed to have primary angiomyolipoma of the spleen.

Conclusions

We have reported the surgical treatment for an extremely rare case of giant splenic angiomyolipoma in a young man. Globally, this is the second report on this condition. We believe that partial splenic resection is a feasible option for the management of giant tumors.

A Review of the Literature on Extrarenal Retroperitoneal Angiomyolipoma

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.

A case of pararenal angiomyolipoma arising from an existing exophytic angiomyolipoma

A 52-year-old healthy woman with a congenital solitary right kidney presented with an incidentally found pararenal mass. Computed tomography and magnetic resonance imaging revealed an exophytic mass in the right kidney consistent with an angiomyolipoma and an additional enhancing pararenal mass that contained fatty elements. Differential diagnosis of the mass included liposarcoma and angiomyolipoma. Upon exploration, the exophytic angiomyolipoma was found to be contiguous with the pararenal mass via an isthmus of fatty tissue. Frozen sections were taken from both masses which confirmed that both were angiomyolipoma. This is the first case reported in the literature wherein an angiomyolipoma extended extrarenally and formed a significantly larger pararenal mass.

Retroperitoneal extrarenal angiomyolipomas: an evidence-based approach to a rare clinical entity

Extrarenal angiomyolipomas (ERAMLs) are rare tumors that present as incidentalomas upon imaging for other conditions. Retroperitoneal ERAMLs present a unique challenge from a diagnostic and treatment standpoint as they can mimic other benign and malignant retroperitoneal tumors. We present a case of a 39-year-old female with a 19.3 cm × 13.5 cm × 10.7 cm left extrarenal retroperitoneal mass. Histopathologic examination and HMB-45 staining revealed the mass to be a retroperitoneal ERAML. Our case report provides a comprehensive literature review and an evidence-based algorithm for taking care of patients with ERAMLs.

Unusual multicentric angiomyolipoma of knee joint and soft tissue foot

To report unusual occurrence of angiomyolipoma at intraarticular location with another lesion in the same side foot. A 12-year-old girl was referred to us after initial inconclusive work-up done elsewhere for swelling of left knee joint. There was a 15 × 12 cm swelling in the knee joint partially encasing patella while also a similar hourglass shaped swelling measuring 9 × 4 cm was noted in the same side foot. After clinical and radiological evaluation an excision biopsy was planned for both sites. The specimen sent for histopathological evaluation revealed angiomyolipoma with identical characteristics in the two locations and was HMB45 immunostain negative. Patient was evaluated for possibility of tuberous sclerosis but there was no contributory evidence. Angiomyolipoma is typically a solitary renal tumor with rare occurrence at musculoskeletal sites. Multicentric variety is still infrequent. Intraarticular occurrence of angiomyolipoma presents a diagnostic challenge not only in terms of unfamiliarity but also unusual presentation with absence of characteristic immunostaining and multicentricity requiring careful exclusion of other lesions that may require a more radical approach for treatment.

Perinephric angiomyolipoma: A unique development pattern surrounding the kidney

We report a case of a 31-year-old man with extrarenal angiomyolipoma of the perinephric space. He presented with asymptomatic macrohematuria. Computed tomography of the abdomen revealed a large perinephric mass which was separated from the right kidney and its unique growth appeared to have surrounded the kidney. Extrarenal angiomyolipomas of the perinephric fat are rare and they should be considered in the differential diagnosis of a retroperitoneal mass where asymptomatic macrohematuria was presented at the onset.

Magnetic Resonance Imaging of Adrenal Angiomyolipoma

Angiomyolipoma is a benign mesenchymal neoplasm that typically occurs in the kidney sporadically or in patients with tuberous sclerosis complex. Extrarenal angiomyolipomas are uncommon, and the liver is the most common extrarenal site. Other sites reported include the bone, colon, heart, lung, parotid gland, skin, spermatic cord, gynecologic regions, and retroperitoneum. A case of an angiomyolipoma involving the right adrenal gland in a 49-year-old female patient with tuberous sclerosis is reported. The magnetic resonance (MR) imaging features are also discussed. Only 2 cases describing adrenal angiomyolipoma were found in the English literature. Neither of these 2 cases was documented in the radiology literature or discussed the MR features of adrenal angiomyolipoma.

Extrarenal retroperitoneal angiomyolipoma: case report and review of the literature

Angiomyolipomas are rare benign tumors that usually occur in the kidneys. Extrarenal angiomyolipomas are extremely uncommon. We describe a case of angiomyolipoma arising in the retroperitoneum that was successfully treated by arterial embolization and surgical excision. The literature on retroperitoneal extrarenal angiomyolipoma and its differential diagnoses is briefly reviewed.

Giant Extrarenal Retroperitoneal Angiomyolipoma: A Case Report and Literature Review

Extrarenal angiomyolipoma is an uncommon disease entity and is rare in the retroperitoneum. We report a case of giant extrarenal retroperitoneal angiomyolipoma mimicking liposarcoma. A 35-year-old woman presented with a history of increased abdominal circumference and urinary frequency. Abdominal computerized tomography demonstrated a 24 x 21 x 16 cm retroperitoneal fatty tumor displacing the right kidney to the left upper quadrant of the abdomen. At laparotomy, the tumor was widely excised and the right kidney was successfully preserved. Final histologic examination identified the tumor as an angiomyolipoma. At 4-month postoperative follow-up, no evidence of tumor recurrence was found and the right kidney was fully functional.

Contemporary diagnosis and management of renal angiomyolipoma

PURPOSE

We present a comprehensive resource that summarizes contemporary advances relevant to the clinical management of renal angiomyolipoma.

MATERIALS AND METHODS

A MEDLINE search was done using the key words angiomyolipoma, hemangioma or lipoma and kidney neoplasm, and therapeutic embolization. References from these articles were reviewed to identify additional relevant source material. We identified 13 series published since 1986 comprising 336 patients as well as 24 reports of therapeutic embolization for angiomyolipoma, comprising 76 patients. To our knowledge we report the largest compilation series to date.

RESULTS

Angiomyolipoma is generally benign, although an uncommon subtype (epithelioid angiomyolipoma) may behave more aggressively. Tuberous sclerosis associated angiomyolipoma tends to be larger, multiple and more likely to cause spontaneous hemorrhage than the sporadic entity. Tumors that hemorrhage tend to be larger. Computerized tomography or magnetic resonance is usually sufficient for diagnosis. Biopsy is rarely useful. Primary indications for intervention include symptoms such as pain or bleeding or suspicion of malignancy. Prophylactic intervention is justifiable for large tumors, in females of childbearing age or in patients in whom followup or access to emergency care may be inadequate. Recent advances that have affected management include improved understanding of tuberous sclerosis complex and angiomyolipoma genetics, the identification of molecular markers that facilitate histopathological diagnosis, and the refinement of embolization and partial nephrectomy techniques.

CONCLUSIONS

Although some cases of angiomyolipoma may require complete nephrectomy, most can be managed by conservative nephron sparing approaches. Ongoing research into the molecular biology and clinical behavior of angiomyolipoma may improve our ability to manage these lesions.

Giant bleeding renal angiomyolipoma: diagnosis and management

A case of a giant bleeding renal angiomyolipoma is presented. The patient was a 40-year-old Egyptian male with no clinical or radiological evidence of tuberous sclerosis. The radiological features and management, including the role of angiography are briefly discussed and the medical reviews on this subject are briefly considered.

Computerized tomography characteristics that differentiate angiomyolipomas from liposarcomas in the perinephric space

PURPOSE

We performed a retrospective study to determine computerized tomography (CT) findings associated with perinephric angiomyolipomas or perinephric liposarcomas.

MATERIALS AND METHODS

During the last 7 years 6 patients with perinephric angiomyolipoma and 12 with perinephric liposarcoma were seen at our hospital. Two radiologists who were blinded to the pathological diagnosis retrospectively evaluated the CT characteristics of perinephric angiomyolipoma and perinephric liposarcoma. The relationship of each CT characteristic with tumor type was compared using Fisher's exact test.

RESULTS

The CT characteristics of perinephric angiomyolipoma were intratumoral linear vascularity (p = 0.001), aneurysmal dilatation (p = 0.025), bridging vessel sign (p = 0.005), hematoma (p = 0.025), beak sign (p = 0.001) and discrete intrarenal fatty tumors (p = 0.025). The CT characteristic of perinephric liposarcoma was a nonfatty soft tissue mass (p = 0.005). There was no significant difference in the presence of calcifications in both groups.

CONCLUSIONS

This retrospective study suggests that analysis of CT characteristics (linear vascularity, aneurysmal dilatation, bridging vessel sign, hematoma, beak sign and discrete intrarenal fatty tumors) may help to differentiate perinephric angiomyolipoma from perinephric liposarcoma.

A case of mediastinal angiomyolipoma

Angiomyolipoma is a common tumor of the kidney but has rarely been found in the mediastinum. We report a case of angiomyolipoma of the posterior mediastinum in a 62-year-old woman. She experienced exertional dyspnea and intermittent cough at admission. Computed tomography indicated a tumor located at the left paravertebral and upper posterior mediastinum and MRI imaging demonstrated a mass with low signal intensity in T1-weighted image at T4-5 level. Thoracotomy was done for surgical removal of the tumor and histologic examination revealed a mesenchymal tumor composed of mature fat, capillaries and smooth muscle fibers. The tumor was immunohistochemically positive for CD34 and factor-VIII (for vascular component) smooth muscle actin (for smooth muscle component) and S-100 protein (for fat component). There have been four case reports about mediastinal angiomyolipoma, namely three Japanese cases and one French case. It is suggested that angiomyolipoma could be considered for the differential diagnosis of mediastinal tumors.

Retroperitoneal epithelioid angiomyolipoma leading to fatal outcome

Epithelioid angiomyolipoma (AML) is a newly established variant of AML, characterized by monomorphous epithelioid cells that show HMB-45 immunopositivity, and it often displays aggressive behavior. To date, they have mostly appeared in the kidneys; however, the present autopsy case of a 43-year-old female without the stigmata of tuberous sclerosis complex had a huge retroperitoneal mass, accompanied by involvement of the regional lymph nodes. Histopathologically, the tumor was composed of round, polygonal or short spindle-shaped monomorphous cells with abundant eosinophilic cytoplasm and large nuclei with frequent multinucleation. Mitotic figures were scattered. Mature fat cells and thick-walled abnormal blood vessels were totally absent. Immunohistochemically, the tumor cells were reactive with HMB-45 and alpha-smooth muscle actin antibodies. In spite of curative surgery and repeated radio- and chemotherapy, the tumor continued to grow and brought about the patient's death 4 years after the initial symptoms. At autopsy, the peritoneal cavity was filled with the tumor mass exceeding 5.5 kg. Histopathological features were essentially the same as those of biopsy samples, but the cellular pleomorphism and emperipolesis were more easily identified. This report calls attention to this unusual manifestation of AML in the retroperitoneum and the importance of distinguishing it from sarcomas and/or paragangliomas.

Angiomyolipoma of the renal sinus: diagnosis by percutaneous biopsy

We report a case of angiomyolipoma of the renal sinus discovered incidentally during an evaluation for microscopic hematuria. Diagnosis was confirmed by percutaneous aspiration biopsy performed with magnetic resonance imaging control allowing differentiation of this entity from other fatty tumors of the renal sinus including liposarcoma, lipoma, and sinus lipomatosis.

Extrarenal angiomyolipomas of the perinephric space in tuberose sclerosis

A case of bilateral angiomyolipomas of the perinephric space in a young Arab woman with tuberose sclerosis is reported. Multiple small angiomyolipomata were present in both kidneys and there was pulmonary involvement. The literature on this very rare occurrence is briefly reviewed.

Imaging of angiomyolipomas

In this article we review renal angiomyolipomas (AMLs) from cases in the world literature and 60 cases from our own institution. We also analyze the role and the place of the various imaging techniques in the detection and diagnosis of AMLs. Discussion is focused on the natural history of this benign neoplasm as an isolated form or as a part of the tuberous sclerosis (TS) complex or as part of a third less certain group of multiple AML without stigmata of TS. We also consider the growth patterns and hemorrhagic risks of AML to help define an approach to the current management of this lesion.

Multifocal angiomyolipoma in a patient with tuberous sclerosis

Angiomyolipomas are rare lesions that occur most commonly in the kidney, but also can occur in the liver and rarely, in the lymph nodes. Its rare association with tuberous sclerosis has been suggested, but never proved. We report a patient with multiple visceral angiomyolipomas as well as visceral vessel aneurysms and tuberous sclerosis. The association of the three lesions suggests a possible common connective-tissue defect.

Renal angiomyolipoma with extrarenal involvement--in vascular, lymph-node and perirenal tissue. Reports of four cases

Extrarenal involvement was found in four cases of renal angiomyolipoma. In one case the wall of the inferior right bronchial artery was infiltrated, lymph nodes were involved in two cases and the perirenal fat in one case. Extrarenal extension does not seem to alter the prognosis of renal angiomyolipoma. Expectant treatment of this rare condition therefore appears to be warranted.

Angiomyxoid tumour in the renal peripelvic tissues with features of aggressive angiomyxoma

A case of angiomyxoid tumour in the renal peripelvic soft tissue of a 45 year old woman is reported. The encapsulated tumour, measuring 12 x 9 x 6 cm, was solid and firm. The cut surface revealed a yellowish-white, gelatinous, and glistening tumour. Histologically, the tumour was composed of loosely textured spindle and stellate cells with prominent blood vessels of variable calibre. The tumour cells stained strongly for vimentin. These findings strongly resemble those associated with aggressive angiomyxoma in the vulva and perineum.

Case report: perinephric angiomyolipomas in tuberous sclerosis

Bilateral large perinephric angiomyolipomas in a young Chinese woman with tuberous sclerosis are reported. Computed tomography (CT) demonstrated large fatty masses, containing abnormally dilated blood vessels and muscle strands, within the Gerota's fascia bilaterally. There were multiple foci of involvement in both kidneys. The diagnosis was confirmed on histological examination of the excised left perinephric angiomyolipoma and nephrectomy specimens. The patient subsequently developed bilateral pneumothoraces which were surgically treated. High resolution CT showed extensive thin-walled cysts in both lungs.

Extrarenal angiomyolipoma with melanocytic and hibernoma-like features

Angiomyolipoma is a tumor commonly occurring in the kidney, but occasionally found in extrarenal sites. Retroperitoneal angiomyolipoma with unusual features presenting in a 39 year old woman with hypertension is reported in this paper. Tumor fat was inconspicuous, and present largely as hibernoma-like microvesicular lipid. Tumor cells also demonstrated positivity for HMB-45 and S-100 protein, and by electron microscopy showed occasional cytoplasmic striated granules indistinguishable from stage II premelanosomes. However, electron microscopy and immunocytochemistry also confirmed the presence of a substantial myogenous component in the tumor, establishing the diagnosis of angiomyolipoma. The implications of these findings, and the role of immunocytochemistry and electron microscopy in the diagnosis of this tumor are discussed.