A 20 year old primigravida was seen at 37+ weeks of gestation. She was married to her first cousin and gave a history of multiple bone overgrowths especially in the lower limb but no history of fractures. She had been diagnosed as having enchondromatosis (Ollier's disease) as a child. There was no other significant past personal or family history.
On examination, non-tender exostoses were noticed in the phalanges of the upper limb and in the long bones of the lower limb. Abdominal examination revealed a well-grown fetus corresponding to gestation. Routine investigations (haemoglobin, blood group and Rhesus typing, rubella, Hepatitis, HIV status) were normal.
She presented again at 38+ weeks of gestation in early labour. Vaginal examination revealed a high presenting part with tense bulging membranes. Some prominence of the bone into the pelvic canal was felt and the membranes were left intact. She declined caesarean section initially. A repeat examination in 4 hours revealed the dilatation of the cervix was 6 cm with high presenting part and the bony prominence was felt on the right side obstructing the pelvic capacity. She was counselled about the possibility of cord prolapse and caesarean section if the membranes were ruptured. Controlled rupture of the membranes was done but loops of cord were felt by the side of the head. An emergency caesarean section was performed and a baby boy weighing 3170 g was delivered with Apgar score of 8 and 9 at 1 and 5 minutes, respectively. She had an uneventful post-operative recovery and was discharged on the fifth post-operative day. Six weeks later, an X-ray of the pelvis showed Ollier-related changes in both hips, pubic bones, left and right iliac bones and a narrow pelvic canal (Fig. 1).
Enchondromatosis (Ollier's disease) is a non-hereditary disorder of enchondral ossification with lesions distributed throughout the tubular and flat bones of the body. Although there are many case reports of this disorder, this is the first report of a patient needing caesarean section due to pelvic enchondromata in the English literature to the best of our knowledge.
The disease is characterised by such delayed and imperfect conversion of epiphyseal cartilage to bone that the metaphyses include a considerable portion of unossified cartilage and are often expanded diffusely by enchondromata, but without exostoses as in diaphyseal aclasia. It does not affect every part of an epiphysis equally. Sometimes there is normal growth on one side of an epiphysis with areas of unconverted cartilage and delayed ossification on the other. In the ilium unossified sectors of cartilage based on the epiphysis at the crest, alternating with areas of more normal bone, give the typical radiographic appearance of a fan which may be a diagnostic sign in doubtful cases. If every part of an epiphysis is involved so that the metaphysis is expanded by a mass of pure hyaline cartilage, fractures are more frequent, despite the misleading appearance of density often observed from secondary calcification of the enchondromata.1
The cause is obscure. There seems to be no hereditary or familial influence, but the selective involvement of the epiphyses, the normal blood chemistry and the occasional association with haemangioma (Maffucci's syndrome) support the view that it is the result of a primary germ cell defect. The presenting clinical manifestations are masses that increase in size as the child grows, asymmetric limb shortening and either genu varus or valgus deformities. Malignant degeneration is well known.2
The differential diagnosis is diaphyseal aclasis (multiple hereditary exostoses) but the radiological features were suggestive of Ollier's disease in this patient.
The presence of musculoskeletal disease elsewhere in the body indicates the need for careful pelvimetry during the antepartum period. Pelvic examination early in the pregnancy or at term also can detect benign osteochondromas of the pelvic wall and sacrum.3 Antenatal pelvimetry, either by X-ray or MRI, could have predicted the condition and she should have been prepared for an elective caesarean section.