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Infantile hemangiopericytoma: A rare cause of a soft tissue mass
Infantile
Hemangiopericytoma: By Charles
A Rare Cause of a Soft Tissue Mass P. Virden
and Frank P. Lynch
San Diego, California 0 A case of infantile hemangiopericytoma in a neonate is presented. The clinicopathologic characteristics of this tumor are described. This tumor is often confused for other more aggressive malignant tumors and, thus, is likely underreported and overtreated. These tumors exhibit features suggestive of malignancy such as increased mitotic activity, nuclear pleomorphism, and increased cellularity, yet are clinically unpredictable. A conservative surgical approach is advocated. Copyright f 1993 by W.B. Saunders Company INDEX WORDS:
Hemangiopericytoma,
infantile.
H
EMANGIOPERICYTOMAS are rare and distinct vascular tumors, accounting for less than 1%) of all types of vascular tumors. This tumor was first described by Stout and Murray in 1942 as “vascular tumors featured by a proliferation of capillaries, and surrounding these were massed spindleshaped or round cells.“’ It is now recognized that the tumor is derived from the pericytes of Zimmerman, which are pericapillary mesenchymal cells with contractile ability.‘J Approximately 10% of the cases occur in chi1dren.l We present a case of infantile hemangiopericytoma in a &week-old girl referred to us for evaluation of a mass in her posterior thigh. CASE
REPORT
The patient was born full term to a X-year-old gravida 2, para 2 woman. The pregnancy and delivery were uncomplicated. The infant required a partial exchange transfusion for high viscosity on the first day of life. She was discharged home shortly after this with an otherwise uncomplicated stay. At 2 weeks of age her mother noticed a right posterior thigh mass while bathing the patient. She hrought the child to the emergency department where an ultrasound of the mass was obtained. A preliminary diagnosis of birth trauma was suspected and the ultrasound was read out as consistent with hematoma. She was told it would resolve with time and not to worry. The mother waited 3 more weeks and contacted her pediatrician when this mass seemed to be enlarging. Her pediatrician immediately referred her to us for surgical evaluation. Physical examination showed a healthy appearing infant in no distress. Her vitals were stable. Her examination was unremarkable except for a posterior thigh mass. The mass was firm and moved in the belly of the biceps femoris muscle as the lower leg was flexed and extended (Fig 1). She was scheduled for excisional biopsy. Preoperative hemogram. serum chemistry. urinalysis, and chest roentgenogram were all normal. Excisional biopsy was performed. The tumor appeared to arise from the medial belly of the long head of the biceps femoris muscle (Fig 2). The mass was excised with a l-cm rim of what appeared to he normal tissue. Grossly the tumor was 3 x 1 x 1.X cm. soft. fleshy. and multinodular in consistency. Histologically, the cellular tumor was composed of a relatively haphazard arrangement of oval tumor cells and abundant vessel\ (Fig 3). The nuclei of the tumor cells
Journa/ofPed/atric
Surgery, Vol 28, No 5 (May), 1993: pp 741.743
manifest minimal pleomorphism. Mitotic activity is low, with less than one mitosis per 10 high-power fields. There was a relatively uniform arrangement of thin-walled, endothelial-lined. branching vascular channels. There was no significant necrosis or hemorrhage. Vimentin stain was used to assist in identifying vascular structures (Fig 4). Electronmicroscopy and immunopathological staining confirmed the diagnosis of infantile hemangiopericytoma. The lesion focally extended to a margin of excision. Postoperatively the patient has undergone magnetic resonance imaging scanning of the chest, abdomen, and posterior thigh, which have all been negative. Clinically she appears disease free and will undergo close observation. DISCUSSION
This rare vascular tumor was tirst described by Stout and Murray in 1942.’ They believed this tumor originated from the contractile pericytes of Zimmerman surrounding the microvasculature. The true incidence of this tumor is difficult to estimate, as it can be mistaken for other similar tumors that are highly vascular. These uncommon mesenchymal tumors usually develop in the fifth and sixth decades and affect males and females equally.> They can occur at any age or in any location”; in children these tumors have a propensity to develop in the head and neck region and lower extremities.’ In adults, the common sites of origin are the retroperitoneum and lower extremities.’ The most difficult issue after the diagnosis has been confirmed is predicting the clinical course based on histological criteria. Enzinger and associates suggest that the most important predictive factor for malignant behavior seems to be the mitotic index, an index of more than 4110 hpf being indicative of malignancy.“.” Other unfavorable histological characteristics are increased cellularity with a high degree of nuclear pleomorphism, and foci of necrosis. Most authors agree that the infantile hemangiopericytoma should be regarded as a separate entity from the adult counterpart due to its benign clinical behavior, often in the face of histological criteria indicative of malignant behavior. In a recent review by Salloum et al. 34 cases of soft tissue tumors other than rhabdomyosarcoma, in infants under 1 year of age were examined.“l They concluded differentiating between malignant
741
742
Fig 1.
VIRDEN AND LYNCH
Soft tissue mass is visible in the posterior midthigh region.
and benign soft tissue tumors was difficult. Of the six patients with a final diagnosis of hemangiopericytoma, five were originally misdiagnosed as having an aggressive malignancy based on histological appearance, and were thus overtreated.“’ Although it appears there is little argument that the infantile hemangiopericytoma acts clinically more benign than the adult hemangiopericytoma, the literature supports the fact that the infantile hemangiopericytoma is potentially malignant.5~*0 A recent case report of a child with congenital hemangiopericytoma showed
Fig 2. View of tumor removed at surgery. Note its multilobulated appearance.
Fig 3. Hematoxylin & eosin stain showing haphazard array of oval tumor cells. Note minimal nuclear pleomorphism and low mitotic index (original magnification x40).
Fig 4. Vimentin stain, red color is staining of vessel wall components (original magnification x40).
INFANTILE
743
HEMANGIOPERICYTOMA
spontaneous tumor regression,” whereas other reports have shown an aggressive behavior of this tumor 12.13 The differential diagnosis of a soft tissue mass in a neonate should include rhabdomyosarcoma, mesenchymal chondrosarcoma, infantile fibrosarcoma, malignant fibrous histiocytoma, malignant schwannoma. vascular leiomyoma, and hemangioendothelioma. Therapy should ideally offer the best chance of long-term survival without severe damage to the
rapidly growing and maturing organs. Infantile hemangiopericytoma is most often present in the subcutaneous tissue. Surgery should be conservative. Wide local excision is the procedure of choice. For unresectable lesions, chemotherapy is considered the next line of therapy. Radiotherapy should be reserved for failure of surgery and chemotherapy. Progress in immunohistochemistry has enabled more accurate identification of the cell type, but the degree of malignancy remains difficult to establish.
REFERENCES L. Stout AP. Murray MR: Hemangopericytoma-A vascular tumor featuring Zimmerman’s pericytes. Am Surg 116:26-33, 1941 2. Fisher ER. Kaufman N, Mason EJ: HemangiopericytomaHistologic and tissue culture studies. Am J Pathol28:653-661. 1952 3. Kuhn C. Rosai J: Tumors arising from thepericytes. ultrastructure and organ culture of a case. Arch Pathol88:653-663. 1969 4. Kauffman SL, Stout AP: Hemangiopericytoma in children. Cancer 13:6Y5-710, 1960 S. McMaster MJ. Some EH, Ivins J: Hemangiopericytoma: A clinicopathologic study and long-term follow-up of 60 patients. Cancer 3612332-2244. 1975 6. Pitluck HC. Corm J: Hemangiopericytoma: Literature review and clinical presentations. Am J Surg 137:413-416, 1979 7. Gerner RE. Moore GE. Pickren JW: Hemangiopericytoma. AnnSurg 179:12X-132, 1974 8. Enzinger FM, Smith BH: Hemangiopericytoma: An analysis of IO6 cases. Hum Pathol 76-82, 1976
9. Enzinger FM, Weiss SW: Soft Tissue Tumors. Moshy, 1983. pp 463481
St Louis, MO.
10. Salloum E. Flamant F. Caillaud JM. et al: Diagnostic and therapeutic problems of soft tissue tumors other than rhabdomyoSarcoma in infants under Lyear of age:A clinicopathological study of 34 cases treated at the Institut Gustave-Roussy. Med Pediatr Oncol 18:37-U. 1990 11. Chen KT. Kassel SH. Medrano VA: Congenital pericytoma. J Surg Oncol31:127-129. 19X6
hemangio-
12. Morgan A, Evbuomwan 1: Congenital hemangiopericytoma of the face with early distant metastasis. J R Coil Surg Edinh 28:123-125. 1983 13. Peace RJ: A congenital neoplasm of the brain of a newhorn infant. Report of a case with necropsy. Am J Clin Pathol 24:12721275.1954
Hemangiopericytoma: By Charles
A Rare Cause of a Soft Tissue Mass P. Virden
and Frank P. Lynch
San Diego, California 0 A case of infantile hemangiopericytoma in a neonate is presented. The clinicopathologic characteristics of this tumor are described. This tumor is often confused for other more aggressive malignant tumors and, thus, is likely underreported and overtreated. These tumors exhibit features suggestive of malignancy such as increased mitotic activity, nuclear pleomorphism, and increased cellularity, yet are clinically unpredictable. A conservative surgical approach is advocated. Copyright f 1993 by W.B. Saunders Company INDEX WORDS:
Hemangiopericytoma,
infantile.
H
EMANGIOPERICYTOMAS are rare and distinct vascular tumors, accounting for less than 1%) of all types of vascular tumors. This tumor was first described by Stout and Murray in 1942 as “vascular tumors featured by a proliferation of capillaries, and surrounding these were massed spindleshaped or round cells.“’ It is now recognized that the tumor is derived from the pericytes of Zimmerman, which are pericapillary mesenchymal cells with contractile ability.‘J Approximately 10% of the cases occur in chi1dren.l We present a case of infantile hemangiopericytoma in a &week-old girl referred to us for evaluation of a mass in her posterior thigh. CASE
REPORT
The patient was born full term to a X-year-old gravida 2, para 2 woman. The pregnancy and delivery were uncomplicated. The infant required a partial exchange transfusion for high viscosity on the first day of life. She was discharged home shortly after this with an otherwise uncomplicated stay. At 2 weeks of age her mother noticed a right posterior thigh mass while bathing the patient. She hrought the child to the emergency department where an ultrasound of the mass was obtained. A preliminary diagnosis of birth trauma was suspected and the ultrasound was read out as consistent with hematoma. She was told it would resolve with time and not to worry. The mother waited 3 more weeks and contacted her pediatrician when this mass seemed to be enlarging. Her pediatrician immediately referred her to us for surgical evaluation. Physical examination showed a healthy appearing infant in no distress. Her vitals were stable. Her examination was unremarkable except for a posterior thigh mass. The mass was firm and moved in the belly of the biceps femoris muscle as the lower leg was flexed and extended (Fig 1). She was scheduled for excisional biopsy. Preoperative hemogram. serum chemistry. urinalysis, and chest roentgenogram were all normal. Excisional biopsy was performed. The tumor appeared to arise from the medial belly of the long head of the biceps femoris muscle (Fig 2). The mass was excised with a l-cm rim of what appeared to he normal tissue. Grossly the tumor was 3 x 1 x 1.X cm. soft. fleshy. and multinodular in consistency. Histologically, the cellular tumor was composed of a relatively haphazard arrangement of oval tumor cells and abundant vessel\ (Fig 3). The nuclei of the tumor cells
Journa/ofPed/atric
Surgery, Vol 28, No 5 (May), 1993: pp 741.743
manifest minimal pleomorphism. Mitotic activity is low, with less than one mitosis per 10 high-power fields. There was a relatively uniform arrangement of thin-walled, endothelial-lined. branching vascular channels. There was no significant necrosis or hemorrhage. Vimentin stain was used to assist in identifying vascular structures (Fig 4). Electronmicroscopy and immunopathological staining confirmed the diagnosis of infantile hemangiopericytoma. The lesion focally extended to a margin of excision. Postoperatively the patient has undergone magnetic resonance imaging scanning of the chest, abdomen, and posterior thigh, which have all been negative. Clinically she appears disease free and will undergo close observation. DISCUSSION
This rare vascular tumor was tirst described by Stout and Murray in 1942.’ They believed this tumor originated from the contractile pericytes of Zimmerman surrounding the microvasculature. The true incidence of this tumor is difficult to estimate, as it can be mistaken for other similar tumors that are highly vascular. These uncommon mesenchymal tumors usually develop in the fifth and sixth decades and affect males and females equally.> They can occur at any age or in any location”; in children these tumors have a propensity to develop in the head and neck region and lower extremities.’ In adults, the common sites of origin are the retroperitoneum and lower extremities.’ The most difficult issue after the diagnosis has been confirmed is predicting the clinical course based on histological criteria. Enzinger and associates suggest that the most important predictive factor for malignant behavior seems to be the mitotic index, an index of more than 4110 hpf being indicative of malignancy.“.” Other unfavorable histological characteristics are increased cellularity with a high degree of nuclear pleomorphism, and foci of necrosis. Most authors agree that the infantile hemangiopericytoma should be regarded as a separate entity from the adult counterpart due to its benign clinical behavior, often in the face of histological criteria indicative of malignant behavior. In a recent review by Salloum et al. 34 cases of soft tissue tumors other than rhabdomyosarcoma, in infants under 1 year of age were examined.“l They concluded differentiating between malignant
741
742
Fig 1.
VIRDEN AND LYNCH
Soft tissue mass is visible in the posterior midthigh region.
and benign soft tissue tumors was difficult. Of the six patients with a final diagnosis of hemangiopericytoma, five were originally misdiagnosed as having an aggressive malignancy based on histological appearance, and were thus overtreated.“’ Although it appears there is little argument that the infantile hemangiopericytoma acts clinically more benign than the adult hemangiopericytoma, the literature supports the fact that the infantile hemangiopericytoma is potentially malignant.5~*0 A recent case report of a child with congenital hemangiopericytoma showed
Fig 2. View of tumor removed at surgery. Note its multilobulated appearance.
Fig 3. Hematoxylin & eosin stain showing haphazard array of oval tumor cells. Note minimal nuclear pleomorphism and low mitotic index (original magnification x40).
Fig 4. Vimentin stain, red color is staining of vessel wall components (original magnification x40).
INFANTILE
743
HEMANGIOPERICYTOMA
spontaneous tumor regression,” whereas other reports have shown an aggressive behavior of this tumor 12.13 The differential diagnosis of a soft tissue mass in a neonate should include rhabdomyosarcoma, mesenchymal chondrosarcoma, infantile fibrosarcoma, malignant fibrous histiocytoma, malignant schwannoma. vascular leiomyoma, and hemangioendothelioma. Therapy should ideally offer the best chance of long-term survival without severe damage to the
rapidly growing and maturing organs. Infantile hemangiopericytoma is most often present in the subcutaneous tissue. Surgery should be conservative. Wide local excision is the procedure of choice. For unresectable lesions, chemotherapy is considered the next line of therapy. Radiotherapy should be reserved for failure of surgery and chemotherapy. Progress in immunohistochemistry has enabled more accurate identification of the cell type, but the degree of malignancy remains difficult to establish.
REFERENCES L. Stout AP. Murray MR: Hemangopericytoma-A vascular tumor featuring Zimmerman’s pericytes. Am Surg 116:26-33, 1941 2. Fisher ER. Kaufman N, Mason EJ: HemangiopericytomaHistologic and tissue culture studies. Am J Pathol28:653-661. 1952 3. Kuhn C. Rosai J: Tumors arising from thepericytes. ultrastructure and organ culture of a case. Arch Pathol88:653-663. 1969 4. Kauffman SL, Stout AP: Hemangiopericytoma in children. Cancer 13:6Y5-710, 1960 S. McMaster MJ. Some EH, Ivins J: Hemangiopericytoma: A clinicopathologic study and long-term follow-up of 60 patients. Cancer 3612332-2244. 1975 6. Pitluck HC. Corm J: Hemangiopericytoma: Literature review and clinical presentations. Am J Surg 137:413-416, 1979 7. Gerner RE. Moore GE. Pickren JW: Hemangiopericytoma. AnnSurg 179:12X-132, 1974 8. Enzinger FM, Smith BH: Hemangiopericytoma: An analysis of IO6 cases. Hum Pathol 76-82, 1976
9. Enzinger FM, Weiss SW: Soft Tissue Tumors. Moshy, 1983. pp 463481
St Louis, MO.
10. Salloum E. Flamant F. Caillaud JM. et al: Diagnostic and therapeutic problems of soft tissue tumors other than rhabdomyoSarcoma in infants under Lyear of age:A clinicopathological study of 34 cases treated at the Institut Gustave-Roussy. Med Pediatr Oncol 18:37-U. 1990 11. Chen KT. Kassel SH. Medrano VA: Congenital pericytoma. J Surg Oncol31:127-129. 19X6
hemangio-
12. Morgan A, Evbuomwan 1: Congenital hemangiopericytoma of the face with early distant metastasis. J R Coil Surg Edinh 28:123-125. 1983 13. Peace RJ: A congenital neoplasm of the brain of a newhorn infant. Report of a case with necropsy. Am J Clin Pathol 24:12721275.1954