Sacrococcygeal chondroma misdiagnosed as pilonidal sinus: A case report

Chordomas are rare bone neoplasms that arise from the remnants of the embryonic notochord. Although chordomas are rare, slow to grow and have low metastatic potential, they can be fatal if diagnosed late or misdiagnosed. We present the case of a 65 years old male patient who presented for pain and discomfort in his buttocks area mainly upon sitting. He had previously undergone three surgeries for resection of what was diagnosed as a pilonidal sinus from the buttock area in a different hospital. After a CT scan being in favor of a developmental cyst, once again surgical resection was done. Postoperative immunohistopathological studies identified the mass as a differentiated conventional type chordoma. In light of these findings, our patient was referred for metastatic workup, radiotherapy and chemotherapy. Their vague symptomatology can lead to frequent misdiagnosis of chordomas. CT scan can easily cause confusion between a benign pilonidal/developmental cyst and a slow growing chordoma. To date, total resection of chordomas is the gold standard of treatment, however, pre-operative biopsy and MRI should be implemented whenever chordoma is among the differentials. Determining the presence of metastasis and assessing local invasions are needed to decide on an appropriate surgical resection (total or partial) and assess the need of chemical (i.e. imatinib mesylate) or radiological treatment. Sacrococcygeal chordomas are rare tumors that are usually misdiagnosed and mismanaged. Imaging can be very helpful in aiding the diagnosis with known suggestive findings especially on MRI. Wide surgical excision is still the ultimate treatment while the use of carbon/photon/hardon radiotherapy and imatinib mesylate is promising.