Background: Myositis ossificans (MO) is a rare non-neoplastic heterotopic ossification of soft tissue. Histological examination is the gold standard method for diagnosis, but fine needle aspiration (FNA) cytology may aid in presumptive diagnosis of this lesion. Cases: Nine patients with chief complaint of soft tissue mass with clinically suspected MO were selected. FNA of the mass showed low to hypercellular smears, composed of some amorphous pink to bluish material on Wright-Giemsa stain. The predominant cells were oval to spindle-shaped, resembling fibroblasts. Some cells had a high nucleo-cytoplasmic ratio with hyperchromatic nuclei, an irregular nuclear border and prominent nucleoli. Bland-looking osteoblasts and uni- and binucleated chondrocytes were also noted. FNA diagnosis of 4 patients was suggestive of osteosarcoma and of 2 patients suggestive of chondrosarcoma, 2 patients were diagnosed with a benign process and 1 was deferred due to hypocellularity of the smears. Histological examination of the corresponding surgical specimen confirmed the diagnosis of MO. Conclusion: MO cannot be diagnosed on FNA smears without analyzing the clinical and radiological findings. Experience shows that otherwise MO is mostly misdiagnosed as a malignant lesion.

Parikh J, Hyare H, Saifuddin A: The imaging features of post-traumatic myositis ossificans, with emphasis on MRI. Clin Radiol 2002;57:1058–1066.
Yazici M, Etensel B, Gursoy H, Aydogdu A, Erkus M: Nontraumatic myositis ossificans with an unusual location: case report. J Pediatr Surg 2002;37:1621–1622.
Ragunanthan N, Sugavanam C: Pseudomalignant myositis ossificans mimicking osteosarcoma: a case report. J Orthop Surg 2006;14:219–221.
Rosa M, Mohammadi A: Myositis ossificans traumatica of the abdominal wall. Can J Surg 2009;52:E33–E34.
Hendifar AE, Johnson D, Arkfeld D: Myositis ossificans: a case report. Arthritis Rheum 2005;53:793–795.
Fernandez JA, Caba-Molina M, Arias-Santiago S, O’Valle F, Hernandez-Cortes P, Aneiros-Cachaza J: Myositis ossificans circumscripta without history of trauma. J Clin Med Res 2010;2:142–144.
Nishio J, Nabeshima K, Iwasaki H, Naito M: Non-traumatic myositis ossificans mimicking a malignant neoplasm in an 83-year-old woman: a case report. J Med Case Reports 2010;4:270.
Dodd LG, Martinez S: Fine-needle aspiration cytology of pseudosarcomatous lesions of soft tissue. Diagn Cytopathol 2001;24:28–35.
Ushigome S, Nikaido T: Diagnostic usefulness of aspiration biopsy cytology in bone tumors and tumor-like lesions. Pathol Case Rev 2001;6:2–7.
Urist MR, Nakagawa M, Nakata N, Nogami H: Experimental myositis ossificans: cartilage and bone formation in muscle in response to a diffusible bone matrix-derived morphogen. Arch Pathol Lab Med 1978;102:312–316.
Blazquez JP, Alonso JV, Mendez CLM, de la Campa JA, Gonzalez AA: Fine needle aspiration cytology of focal myositis. Acta Cytol 2005;49:653–655.
Barwad A, Banik T, Gorsi U, Dey P: Fine needle aspiration cytology of myositis ossificans. Diagn Cytopathol 2011;39:432–434.
Aisner SC, Burke KC, Resnik CS: Aspiration cytology of heterotopic ossification. A case report. Acta Cytol 1992;36:159–162.
Tunç M, Ekinci C: Chondrosarcoma diagnosed with fine needle aspiration cytology. Acta Cytol 1996;40:283–288.
Iyer VK: Cytology of soft tissue tumors: benign soft tissue tumors including reactive, nonneoplastic lesions. J Cytol 2008;25:81–86.
Domanski HA, Akerman M: Fine-needle aspiration of primary osteosarcoma: a cytological-histological study. Diagn Cytopathol 2005;32:269–275.
Nagira K, Yamamoto T, Akisue T, Marui T, Hitora T, Nakatani T, Kurosaka M, Tsukamoto R: Scrape and fine-needle aspiration cytology of extraskeletal osteosarcoma. Diagn Cytopathol 2002;27:177–180.
Layfield LJ, Andres KH, Glasgow BJ, Mirra JM: Fine-needle aspiration of primary soft-tissue lesions. Arch Pathol Lab Med 1986;110:420–424.
Akerman M: Fine-needle aspiration cytology of soft tissue sarcoma: benefits and limitations. Sarcoma 1998;2:155–161.
Domanski HA: Fine-needle aspiration cytology of soft tissue lesions: diagnostic challenges. Diagn Cytopathol 2007;35:768–773.
Ng VY, Thomas K, Crist M, Wakely PE Jr, Mayerson J: Fine needle aspiration for clinical triage of extremity soft tissue masses. Clin Orthop Relat Res 2010;468:1120–1128.
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