A Memorable Case Report
Fibrodysplasia
ossificans progressiva
T.
Anna Simon, MD
Department of Child Health
Contact:
Anna Simon, MD
Associate Professor,
Department of Child Health,
Telephone No. 0416-2283350
Email: child1@cmcvellore.ac.in
Key words: fibrodysplasia ossificans
progressiva, myositis ossificans.
Abstract
Fibrodysplasia
ossificans progressiva (FOP) is a rare genetic disease. It is characterized by
widespread soft tissue ossification and congenital anomalies of the extremities.
We report a 6 year old boy who was diagnosed as FOP on the basis of heterotopic
calcification and hallux valgus.
Introduction
Fibrodysplasia
ossificans progressiva (FOP) is a rare autosomal dominant disorder of
connective tissue characterized by congenital malformation of the great toes
and by progressive post-natal heterotopic ossification of soft tissue. We report a 6 year old boy who was diagnosed
as FOP on basis of heterotopic calcification and deformities of great toes.
Case
Report
A 6-year-old male child presented with a
bony swelling over scapula and back of
the neck with restrictions of movement of neck towards right side for
the past 6 months. At 2 years of age he
had empyema on right side for which thoracotomy and drainage was done. He was
the first child born to non-consanguineous parents by cesearean section. His
development was normal. On examination,
his weight was 20 kgs, height was 119 cms and head cirumference was 53 cms. He
had torticollis towards right side. He had bony swelling over the right scapula
over the thorocotomy scar and also on back side of neck (Fig.1a). He had
restriction of movements of right shoulder. His thumb was stiff and hallux
valgus deformity was seen in both the great toes (Fig 1b). His systemic examination
did not reveal any other abnormality. Laboratory investigations revealed serum calcium of 9.5 mg%, phosphorus 5.3 mg% and alkaline phosphate 513 IU/L.
Fig 1a. 6 year old male child having a bony
swelling over the scapula and back side of neck. Note the torticollis towards right side.
Fig 1b. Hallux valgus deformity of great
toes
His skeletal
radiographs revealed ectopic calcification over the right scapula. The
calcification extended into the posterior facial planes of the neck (Fig.2).
Fig 2. Skeletal radiograph showing ectopic
calcification over the right scapula. The calcification extending into the
posterior facial planes of neck
He was diagnosed to have FOP on the basis
of typical radiological features and hallux valgus. He was advised to take
steroids during acute flare-ups followed by non-steroidal anti-inflammatory
drugs. Intravenous pamidronate was recommended every 3 months to prevent
further progression.
Discussion:
Gay Patin in 1962
described the first case of FOP as a woman who “turned into a log of wood”. [1]
FOP is a disease of the mesodermal tissue, characterized by initial
inflammation followed by subsequent proliferation of the fibrous tissue and
formation of ectopic bone tissue. Its incidence is one case per two million. It
is a disorder which generally occurs in the first three decades of life, and a
majority of patients have onset of symptoms by the age of four years, but there
can be a delay of many months before the diagnosis is made. [2] The disease
predominantly affects boys. It is transmitted as a dominant trait.
The
ectopic bone tissue formed is located in soft parts, mainly in the connective
tissue of the striated musculature. The lesions begin in the paravertebral musculature
and progress into the scapula, proximal portion of the arms, pelvis, jaw and
skull. [3] The ossification process can intensify in the presence of trauma, as
occurred in our case. Exacerbation of FOP may occur spontaneously or be
precipitated by trauma, such as intramuscular injections including vaccines
[4], local anesthesia, muscle biopsy and careless venipuncture. Biopsy of
calcified nodules is to be avoided if the diagnosis of FOP is clear on clinical
and radiological grounds. Biopsy may result in recurrent ossification of the
site, sometimes worse than the original lesion.
Symmetrical congenital malformations of the hands and feet occur in up
to 90% of the cases and are considered essential for its diagnosis. [5] The
most frequent congenital abnormalities are hypoplasia of the thumbs, big toes
and hallux valgus. These are due to shortening of the first phalanges, as
observed in our child.
There are no
specific laboratory alterations in FOP. Skeletal radiography is the
preferential examination for its diagnosis and follow-up, by depicting the
appearance of new ossification. Bone scintigraphy with 99mTc-
To date, there is
no effective therapy to impede progression of the disease. However, several
drugs have been suggested for the treatment of FOP such as retinoic acid [8],
warfarin, and diphosphonates. [9] Corticosteroids can be useful for the acute
process, but they do not prevent ectopic calcification. Some authors have
demonstrated that the use of oral or intravenous diphosphonate appears to be a
therapeutic alternative to reduce ectopic calcifications. [10]
References
1. Lutwak L. Myositis
ossificans progressiva. Mineral, metabolic and radioactive calcium studies of
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2. Connor JM, Evans
OA. Genetic aspects of fibrodysplasia
ossificans progressiva. J Med Genet. 1982;19:35-39.
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Niwayama G. Soft tissues. In: Resnick D, editor. Diagnosis of Bone and joints
disorders. 3rd Ed. Philadelphia; W.B. Saunders Company 1995. p. 4588- 4593.
4. Lanchoney TF,
Cohen RB, Rocke DM, Zasloff MA, Kaplan FS.
Permanent heterotopic ossification at the injection site after
diphtheria-tetanus-pertussis immunizations in children who
have fibrodysplasia ossificans progressiva.
J Pediatr. 1995;126:762-764.
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Zasloff MA. The hand and foot malformations in fibrodysplasia ossificans
progressiva. Johns
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JP, Geho WB. Use and complications of high dose disodium etidronate therapy in
fibrodysplasia ossificans progressiva. J Pediatr. 1977;91:1011-1014.
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Meunier PJ. Effects of intravenous etidronate and oral corticosteroids in
fibrodysplasia ossificans progressiva. Clin Orthop Rel Res. 1998;346:117-120.