Question 1 Answer
C. Bony Abnormality
Question 2 Answer
D. Surgical Excision
Discussion
Diagnostic work-up showed a normal hemogram (Hemoglobin 11.3 gm/dl;
Total leucocyte count: 6620/cumm; Platelets: 5.27 lacs/cumm). The
coagulation profile was also normal (INR: 1.16; Activated partial
thromboplastin time: 29.6 seconds, Control: 27.8 seconds). Chest
radiograph showed complete right-sided homogenous opacity with a
mediastinal shift towards the left side. Ultrasound thorax showed a
right-sided pleural effusion with increased echogenicity suggestive of
hemothorax. A skeletal survey revealed multiple bony outgrowths
originating in the juxta-epiphyseal region of long bones involving all
four limbs. Computed tomography (CT) thorax showed bilateral bony
outgrowths from ribs with right-sided hemothorax (Question-1). A
diagnosis of multiple exostoses was made. Video-assisted thoracoscopic
surgery (VATS) was performed on the right side with resection of rib
exostosis and hemothorax evacuation. Histopathological examination of
excised tissue was suggestive of osteochondroma. Clinical exome
sequencing showed a heterozygous mutation in Exon 6 of the EXT1 (-)
gene, establishing the diagnosis of Hereditary Multiple
Osteochondromas/Exostoses (HMO/HME). The child did well on follow-up at
one year with no recurrence of symptoms.
HME is an autosomal dominant skeletal disorder caused by a
heterozygous pathogenic variant involving the EXT1 or EXT2 genes (1). It
is characterized by multiple benign osteochondromas (exostoses)
involving the metaphyseal region of long bones. The exact prevalence is
not known. There is no gender predisposition; however, males tend to be
more severely affected (2). Clinical features depend on the location of
the exostoses. Clinical symptoms can occur due to osteoarticular
complications like fractures, deformities, osteomyelitis, or compression
of adjacent structures due to bony outgrowths, i.e., nerve or vascular
compression. Positive family history is reported in most cases (1, 2).
In approximately 10% of cases, de novo mutation occurs. The femur is the
most common bone involved, followed by the tibia. Rib exostoses have
been reported in approximately 35-45% of cases, which are primarily
asymptomatic (3).
Hemothorax as a complication of HME is very rare and has been
reported in only 15 patients. It has a male preponderance, with an
average age of presentation being 11.7 years. Chest pain and shortness
of breath are the most common symptoms, as in our index case (4). The
estimated incidence of malignant degeneration to chondrosarcoma is
around 2%-5%. Diagnosis can be established with chest radiographs and CT
thorax in appropriate clinical settings. In cases where a normal chest
x-ray results but there is a strong clinical suspicion, the patient must
be evaluated with a CT thorax. Surgical treatment with resection of
exostoses is the preferred treatment modality in symptomatic cases, VATS
being the preferred approach (Question-2). In addition to acute
management, resection of exostoses prevents the recurrence risk of
hemothorax, establishes the histopathological diagnosis, rules out
malignancy, and minimizes the risk of future malignant degeneration (5).
After resection, the estimated recurrence of exostoses is 2% in
solitary osteochondroma during the pre-pubertal period. Recurrence in
multiple exostoses has not been reported (4,5). More clarity regarding
managing asymptomatic costal exostoses is needed. A conservative
approach is mainly followed. The index case also had exostoses involving
left hemithorax, for which no intervention was done. He remained well
on follow up. Similarly, all asymptomatic osteochondromas remain
symptom-free during follow-up in a case series by Bakshi H et al. (5).
However, these patients must remain under close surveillance to look for
any complications due to exostoses growth, especially during a
pre-pubertal phase or malignant degeneration.
In conclusion, hemothorax is a rare complication of HME in children.
CT scan is usually required to establish the diagnosis. Excision of rib
exostoses in symptomatic children is the mainstay of treatment with an
excellent outcome.
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