METHODSĀ :
A radiological work-up was ordered, which revealed heterogeneous bone
lysis in the coccyx on the standard X-ray (figure 1). The CT scan of the
pelvis showed an expansive, poorly defined osteolytic lesion of the
sacrum with predominantly right lateral extension and invasion of the
gluteus maximus and medius (figure 2). The MRI revealed an aggressive
sacrococcygeal tumour mass infiltrating and invading the right gluteus
maximus (figure 3). The initial clinical and radiological findings
indicated a primary or metastatic malignant tumour. A negative extension
work-up was conducted, which included a thoraco-abdominal CT scan,
cervical ultrasound, mammography, X-ray of the cervical spine
(chordoma), bone scan, specialist gynaecological examination, and
tuberculosis work-up. The patient underwent a posterior sacral biopsy,
which revealed a multivesicular cystic lesion consistent with a hydatid
cyst of the sacrum(figure4), subsequently confirmed by
anatomopathological examination. The lesion was almost completely
excised and the cystic bed was sterilised using hypertonic serum and
hydrogen peroxide, with the installation of a drainage system.
CONCLUSION AND RESULTSĀ :
The immediate postoperative period was uneventful, with resolution of
the signs of compression.
At the 10-month follow-up, the patient showed no signs of recurrence,
and the cystic bed had progressively ossified.