Retroperitoneal extraskeletal osteosarcoma with cystic change arising from heterotopic ossification: a rare entity

  • Kiran Agarwal Professor, Department of Pathology, Lady Hardinge Medical College and Smt S.K. Hospital, Shaheed Bhagat Singh Marg, New Delhi 110001, India
  • Savita Agarwal Department of Pathology, Lady Hardinge Medical College and Smt S.K. Hospital, Shaheed Bhagat Singh Marg, New Delhi 110001, India
  • Lokesh Kumar Assistatnt Professor Department of Radiodiagnosis FH Medial College NH-2, Near Etmadpur Railway ovrbridge, Tundla, Firozabad, Uttar Pradesh
Keywords: Extraskeletal, Osteosarcoma, Myosistis ossificans, Heterotopic ossification, Retroperitoneum.


Extraskeletal osteosarcoma arising from myositis ossificans or heterotopic benign ossification is an extremely rare entity. Heterotopic ossification under rare circumstances may undergo malignant transformation and give rise to extraskeletal osteosarcoma however diagnosis of such transformation requires the presence of a remnant of the benign precursor lesion. Most of the cases reported as secondary extraskeletal osteosarcoma did not contain residual tissue of the previous benign condition and its presence was suggested solely on the basis of clinical course without any histopathological or radiological evidences. We describe a case of secondary extraskeletal osteosarcoma of retroperitoneum showing morphologic evidence of heterotopic benign ossification with extensive cystic change in an eighty- five year old female.


1. Aboulafia AJ, Brooks F, Piratzky J, Weiss S. Osteosarcoma arising from heterotopic ossification after an electrical burn. A case report. J Bone Joint Surg Am. 1999;81:564-70.

2. De Santis E, Rosa MA, Gasparini G. Circumscribed spontaneous heterotopic ossification in the soft tissues simulating sarcoma. Ital J Orthop Traumatol. 1987;13:207-17.

3. Chai ZW, Wang JJ, Song HY, He J. Spontaneous heterotopic ossification around the hip joint: a case report. Zhongguo Gu Shang. 2009;22:65.

4. Shipley AM. Ossifying hematoma and allied conditions. Arch Surg. 1940; 41:516-24.

5. Pack GT, Braund RR. The development of sarcoma in myositis ossificans report of three cases. JAMA. 1942;119:776-9.

6. Kuhlmann RF, Lavell TE. Juxtacortical osteogenic sarcoma following trauma: case report. Ann Surg. 1965;162:1087-90.

7. Sordillo PP, Hajdu SI, Magill GB, Golbey RB. Extraosseous osteogenic sarcoma. A review of 48 patients. Cancer. 1983;51:727-34.

8. Bane BL, Evans HL, Ro JY, Carrasco CH, Grignon DJ, Benjamin RS. Extraskeletal osteosarcoma. A clinicopathologic review of 26 cases. Cancer. 1990;65:2762-70.

9. Secil M, Mungan U, Yorukoglu K, Dicle O. Case 89: Retroperitoneal extraskeletal osteosarcoma. Radiology. 2005;237:880-3.

10. Huvos AG. The spontaneous transformation of benign into malignant soft tissue tumors (with emphasis on extraskeletal osseous, lipomatous and Schwannian lesions). (Suppl) Am J Surg Pathol. 1985;9:7–20.

11. Eckardt JJ, Ivins JC, Perry HO, Unni KK. Osteosarcoma arising in heterotopic ossification of dermatomyositis: case report and review of the literature. Cancer. 1981;48:1256-61.

12. Valderrama E, Kahn LB, Wind E. Extraskeletal osteosarcoma arising in an ectopic hamartomatous thymus. Report of a case and review of the literature. Cancer. 1983;51:1132-7.

13. Konishi E, Kusuzaki K, Murata H, Tsuchihashi Y, Beabout JW, Unni KK. Extraskeletal osteosarcoma arising in myositis ossificans. Skeletal Radiol. 2001;30:39-43.

14. Goyal P, Sehgal S, Agarwal R, Singh S, Gupta R, Kumar A. Ossifying fibromyxoid tumor -Diagnostic challenge for a cytopathologist. Cytojournal. 2012;9:17

15. Rosenberg AE, Heim S. Extraskeletal osteosarcoma. In, Pathology and Genetics of Tumors of Soft Tissue and Bone, World Health Organization Classification of Tumours. Edited by Christopher D.M. Fletcher, Krisjnan Unni and Fredrik Mertens. France: IARC Press, 2002: 182–183.

16. Fang Z, Yokoyama R, Mukai K, Beppu Y and Fukuma H. Extraskeletal osteosarcoma: a clinicopathologic study of four cases. Jpn J Clin Oncol. 1995;25: 55- 60.
Case Report