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Anastomosing haemangioma of kidney: a rare subtype of vascular tumour of the kidney mimicking angiosarcoma A 57-year-old gentleman of New Zealand European ethnicity was referred by his general practitioner (GP) when he was incidentally found to have a 4.2 × 4.0 × 3.5-cm left sided renal mass on an ultrasound scan performed for urinary tract infection. He was asymptomatic with normal examination and urine. A computed tomography (CT) intravenous urogram was performed that showed 46 mm of irregularly enhancing soft-tissue mass with both solid and cystic components (Fig.1). There was possible early invasion of a draining vein on the CT scan but there was no evidence of lymphatic or distal metastasis. He had an uncomplicated left nephrectomy and was discharged home on post-operative day 4. Macroscopically, it was a 3-cm haemorrhagic tumour in the renal hilum, partially cystic and present in the renal vein. Microscopic assessment of the specimen showed that it was a vascular tumour, partly confined within the renal vein, consisted mostly of small thin-walled blood vessels with mild cytological atypia of lining endothelial cells and anastomosis of blood vessels (Fig.2). There was no endothelial multilayering or mitotic activity; it was partly degenerated and in places, the tumour has an infiltrative appearance into fat. CD31 and CD34 positivity demonstrated the endothelial origin of the tumour. Initial impression was an atypical vascular tumour. An external opinion was taken and the final histological diagnosis was anastomosing haemangioma of the genitourinary tract. The patient was seen in outpatients a month later. No post-operative complications were seen, and he was returned back to the care of GP with the advice of repeating a renal ultrasound scan in 1 year’s time to exclude recurrence. Visceral haemangiomas are uncommon. Liver is the most frequent site and renal haemangiomas are rare.1 Histologically, most of the renal haemangiomas are classified as capillary or cavernous subtypes.2 Montgomery and Epstein3 in 2009 described a new variant of capillary haemangioma with an unusual sinusoidal pattern reminis-
cent of splenic parenchyma, which they called ‘anastomosing haemangioma of the genitourinary tract’ most frequently found in kidney. Follow-up of the cases reported so far shows that the tumour is more common in men, in patients with end-stage renal failure and is most frequently found in the renal hilum.1 Most cases are found incidentally on imaging or nephrectomy performed for other reasons,4,5 and are clinically and radiologically undistinguishable from other renal tumours. Clinical features can include haematuria, flank pain and lower urinary tract symptoms.1 Macroscopically, the tumour is well demarcated, not capsulated with a mahogany brown spongy consistency.3,5 Microscopically, the tumour has a unique anastomosing pattern that gives it its name. It has a unique sinusoidal architecture with anastomosing small capillaries.3,5 The capillaries are lined by hobnail endothelial cells and are surrounded by fibrous supporting stromal tissue.3,5 These features make it resemble the splenic parenchyma.3 There are zones of central necrosis in tumour stroma with sclerosis and deposition of collagen between sinusoidal vessels.3,4 Cytologically, the tumour cells are innocent in general without marked nuclear atypia, spindle cells and increased mitotic or apoptotic activity.3 Immunochemically, the tumour is positive for CD31, CD34 and factor VIII-related antigen, which confirm the endothelial origin of the tumour.3,6 The histiogenesis of the tumour is unclear.1 Radiological imaging does not help in differentiating it from other renal tumours.1 Because of the inability to differentiate between anastomosing haemangioma and other aggressive tumours both
Fig. 1. Computed tomography appearance of the tumour.
Fig. 2. Anastomosing blood vessels and hobnail endothelial cells.
© 2014 Royal Australasian College of Surgeons
ANZ J Surg •• (2014) ••–••
2
clinically and radiologically, the surgical intervention is usually the preferred option.6 However, this tumour is new to the literature and long-term follow-up is required to assess the possibility of recurrence and to be exactly sure about the biological nature of this tumour.
References 1. Zhao M, Li C, Zheng J, Sun K. Anastomosing haemangioma of the kidney: a case report of a rare subtype of haemangioma mimicking angiosarcoma and review of literature. Int. J. Clin. Exp. Pathol. 2013; 6: 757–65. 2. Eble JN, Sauter G, Epstein JI et al. World Health Organization classification of tumours. Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. Lyon: IARC press, 2004; 7–85. 3. Montgomery E, Epstein JI. Anastomosing haemangioma of the genitourinary tract: a lesion mimicking angiosarcoma. Am. J. Surg. Pathol. 2009; 33: 1364–9.
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4. Kryvenko ON, Gupta NS, Meier FA, Lee MW, Epstein JI. Anastomosing haemangioma of the genitourinary system: eight cases in the kidney and ovary with immunohistochemical and ultra structural analysis. Am. J. Clin. Pathol. 2011; 136: 450–7. 5. Brown JG, Folpe AL, Rao P et al. Primary vascular tumours and tumourlike lesions of the kidney: a clinicopathologic analysis of 25 cases. Am. J. Surg. Pathol. 2010; 34: 942–9. 6. Wetherell DR, Skene A, Manya K, Manecksha RP, Chan Y, Bolton DM. Anastomosing haemangioma of the kidney: a rare morphological variant of haemangioma characteristic of genitourinary tract location. Pathology 2013; 45: 193–6.
Muazzam Tahir,* MBBS Adrian Folwell,† FRACS Departments of *Surgery and †Urology, Taranaki Base Hospital, New Plymouth, Taranaki, New Zealand doi: 10.1111/ans.12779
© 2014 Royal Australasian College of Surgeons
Anastomosing haemangioma of kidney: a rare subtype of vascular tumour of the kidney mimicking angiosarcoma A 57-year-old gentleman of New Zealand European ethnicity was referred by his general practitioner (GP) when he was incidentally found to have a 4.2 × 4.0 × 3.5-cm left sided renal mass on an ultrasound scan performed for urinary tract infection. He was asymptomatic with normal examination and urine. A computed tomography (CT) intravenous urogram was performed that showed 46 mm of irregularly enhancing soft-tissue mass with both solid and cystic components (Fig.1). There was possible early invasion of a draining vein on the CT scan but there was no evidence of lymphatic or distal metastasis. He had an uncomplicated left nephrectomy and was discharged home on post-operative day 4. Macroscopically, it was a 3-cm haemorrhagic tumour in the renal hilum, partially cystic and present in the renal vein. Microscopic assessment of the specimen showed that it was a vascular tumour, partly confined within the renal vein, consisted mostly of small thin-walled blood vessels with mild cytological atypia of lining endothelial cells and anastomosis of blood vessels (Fig.2). There was no endothelial multilayering or mitotic activity; it was partly degenerated and in places, the tumour has an infiltrative appearance into fat. CD31 and CD34 positivity demonstrated the endothelial origin of the tumour. Initial impression was an atypical vascular tumour. An external opinion was taken and the final histological diagnosis was anastomosing haemangioma of the genitourinary tract. The patient was seen in outpatients a month later. No post-operative complications were seen, and he was returned back to the care of GP with the advice of repeating a renal ultrasound scan in 1 year’s time to exclude recurrence. Visceral haemangiomas are uncommon. Liver is the most frequent site and renal haemangiomas are rare.1 Histologically, most of the renal haemangiomas are classified as capillary or cavernous subtypes.2 Montgomery and Epstein3 in 2009 described a new variant of capillary haemangioma with an unusual sinusoidal pattern reminis-
cent of splenic parenchyma, which they called ‘anastomosing haemangioma of the genitourinary tract’ most frequently found in kidney. Follow-up of the cases reported so far shows that the tumour is more common in men, in patients with end-stage renal failure and is most frequently found in the renal hilum.1 Most cases are found incidentally on imaging or nephrectomy performed for other reasons,4,5 and are clinically and radiologically undistinguishable from other renal tumours. Clinical features can include haematuria, flank pain and lower urinary tract symptoms.1 Macroscopically, the tumour is well demarcated, not capsulated with a mahogany brown spongy consistency.3,5 Microscopically, the tumour has a unique anastomosing pattern that gives it its name. It has a unique sinusoidal architecture with anastomosing small capillaries.3,5 The capillaries are lined by hobnail endothelial cells and are surrounded by fibrous supporting stromal tissue.3,5 These features make it resemble the splenic parenchyma.3 There are zones of central necrosis in tumour stroma with sclerosis and deposition of collagen between sinusoidal vessels.3,4 Cytologically, the tumour cells are innocent in general without marked nuclear atypia, spindle cells and increased mitotic or apoptotic activity.3 Immunochemically, the tumour is positive for CD31, CD34 and factor VIII-related antigen, which confirm the endothelial origin of the tumour.3,6 The histiogenesis of the tumour is unclear.1 Radiological imaging does not help in differentiating it from other renal tumours.1 Because of the inability to differentiate between anastomosing haemangioma and other aggressive tumours both
Fig. 1. Computed tomography appearance of the tumour.
Fig. 2. Anastomosing blood vessels and hobnail endothelial cells.
© 2014 Royal Australasian College of Surgeons
ANZ J Surg •• (2014) ••–••
2
clinically and radiologically, the surgical intervention is usually the preferred option.6 However, this tumour is new to the literature and long-term follow-up is required to assess the possibility of recurrence and to be exactly sure about the biological nature of this tumour.
References 1. Zhao M, Li C, Zheng J, Sun K. Anastomosing haemangioma of the kidney: a case report of a rare subtype of haemangioma mimicking angiosarcoma and review of literature. Int. J. Clin. Exp. Pathol. 2013; 6: 757–65. 2. Eble JN, Sauter G, Epstein JI et al. World Health Organization classification of tumours. Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. Lyon: IARC press, 2004; 7–85. 3. Montgomery E, Epstein JI. Anastomosing haemangioma of the genitourinary tract: a lesion mimicking angiosarcoma. Am. J. Surg. Pathol. 2009; 33: 1364–9.
Images for surgeons
4. Kryvenko ON, Gupta NS, Meier FA, Lee MW, Epstein JI. Anastomosing haemangioma of the genitourinary system: eight cases in the kidney and ovary with immunohistochemical and ultra structural analysis. Am. J. Clin. Pathol. 2011; 136: 450–7. 5. Brown JG, Folpe AL, Rao P et al. Primary vascular tumours and tumourlike lesions of the kidney: a clinicopathologic analysis of 25 cases. Am. J. Surg. Pathol. 2010; 34: 942–9. 6. Wetherell DR, Skene A, Manya K, Manecksha RP, Chan Y, Bolton DM. Anastomosing haemangioma of the kidney: a rare morphological variant of haemangioma characteristic of genitourinary tract location. Pathology 2013; 45: 193–6.
Muazzam Tahir,* MBBS Adrian Folwell,† FRACS Departments of *Surgery and †Urology, Taranaki Base Hospital, New Plymouth, Taranaki, New Zealand doi: 10.1111/ans.12779
© 2014 Royal Australasian College of Surgeons
