Noninvasive sacral chordoma presenting as a benign soft tissue mass.

In this case report, we describe a sacral chordoma, which had an atypical presentation as a mobile, encapsulated, benign soft tissue mass. The patient was asymptomatic, except for the slight enlargement of this lesion. Biopsy of this mass showed a lobulated tumor with bland neoplastic cells in a rich myxoid matrix with the classical immunohistochemical profile of chordoma. Opposite to this classical histological picture of chordoma, the imaging studies (computed tomography and magnetic resonance imaging) could not find any sacral involvement or lytic destruction. Surgical excision of this chordoma confirmed all preoperative findings and diagnoses, showing an encapsulated mass in the sacral soft tissue that has not invaded into the sacrum. This chordoma originated from the sacrococcygeal joint and grew parallel to the sacrum and below the skin. At the same time, histological sections and immunostains reconfirmed diagnosis of chordoma.