|Year : 2014 | Volume
| Issue : 3 | Page : 202-205
Jacob's disease: A rare case report
Nalla Viveka Vardhan Reddy, Ritesh Rajan, Vijaya Kumar Rachalapally, Shanmukha Reddy Kallam
Department of Oral & Maxillofacial Surgery, SVS Institute of Dental Sciences, Mahabubnagar, Andhra Pradesh, India
|Date of Web Publication||17-Sep-2014|
Nalla Viveka Vardhan Reddy
Department of Oral & Maxillofacial Surgery, SVS Institute of Dental Sciences, Mahabubnagar, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Osteochondromas of the skeleton are common tumors, in the facial skeleton they appear on the skull base, maxilla and sometimes in mandibular condyle. Osteochondroma of the coronoid is rare and joint formation with the zygoma is called Jacob's disease.
Keywords: Jacob′s disease, osteochondroma, osteochondroma of coronoid and zygoma
|How to cite this article:|
Reddy NV, Rajan R, Rachalapally VK, Kallam SR. Jacob's disease: A rare case report. J NTR Univ Health Sci 2014;3:202-5
| Introduction|| |
Jacob's disease is a rare condition consisting of new joint formation between the coronoid process of the mandible and the inner aspect of the zygomatic arch. It was first reported by French Anatomist Oscar Jacob in 1899 although Von Langenbeck in 1853 had described coronoid process hyperplasia. The pathogenesis of these conditions is still unclear. ,,,,,
Jacob described an osteochondroma of the coronoid process forming a pseudarthrosis between zygoma and coronoid. Though osteochondroma is a common benign tumor of the skeleton, coronoid process of the mandible is a rare location.  Most of these lesions grow like a mushroom on the coronoid process and do not destroy the coronoid. These tumors grow insidiously and may cause expansion of the zygoma or the zygomatic arch.  The most common presenting complaint is a progressive decrease of mouth opening and facial deformity. ,,
Nearly 70%of cases reported in the literature are men and below the age of 40 years.  Panoramic radiography and paranasal radiographs are useful, but computed tomography (CT) is very valuable in demonstrating the relationship of the mass to the zygoma. Technetium bone scans and single photon emission CT have also been described. 
Surgical excision is the only treatment reported and recurrence rare. Extraoral, intraoral or a combined approach has been described.
Histopathological examination of the tumor has shown that the center of the tumor includes endochondral ossification regions enclosed by hyaline cartilage. Growth of an osteochondroma is similar to that which occurs at the epiphysis, with the cap of cartilage acting as an epiphyseal plate. 
Because of its insidious clinical onset this condition often mimics temporomandibular joint (TMJ) dysfunction and is usually treated as such. Hence Jacob's disease should be included in the list of differential diagnosis of a condition that may result in restricted mouth opening in a patient.
| Case report|| |
A 21-year-old female patient reported to our unit with a complaint of a mild intermittent dull aching pain on the right side of face radiating to the temporal region. Pain was aggravated on chewing food. Patient also gave a history of progressive decrease in mouth opening for the past 1 years.
Clinical examination revealed a mild increase in the right malar eminence. There was a limitation in the mouth opening. Maximal interincisal distance was 12 mm [Figure 1]. There was a deviation of mandible to the left side. TMJ examination did not reveal any abnormality. Intraoral examination was performed, there was a full complement of teeth, on palpation there was mild tenderness on the anterior border of ramus and the zygomatic buttress area on the right side.
An orthopantomogram was obtained; there was an elongation of the coronoid process with an increased radiopacity at the tip of the coronoid and infratemporal region. In light of these findings patient was subjected to CT scan of the facial bones with 3D reconstruction.
|Figure 1: Pre-operative frontal image showing limitation of mouth opening and swelling in the malar region|
Click here to view
CT revealed a typical mushroom shaped growth of the coronoid process measuring 3 cm × 3 cm. There was an appearance of a joint like condition between growth and the zygoma [Figure 2].
|Figure 2: Sagittal scan shows typical mushroom shaped growth of coronoid with fusion of zygoma|
Click here to view
Patient was posted for surgery; awake fiber optic assisted nasotracheal intubation was carried out. Al-Kayat Bramley incision was utilized to approach the tumor. A modification in the dissection included incorporating the deeper laminae of the deep temporal fascia high up in the incision, into the skin flap to provide added protection to the branches of the facial nerve.
Tumor was exposed [Figure 3]; it was noted to have a cartilaginous joint formation with infratemporal surface of the zygoma. The zygomatic arch was osteotomized to facilitate better access to the tumor. It was swung laterally pedicled on the masseter. Tumor excision was begun by placing an osteotomy cut from the anterior border of ramus until the sigmoid notch [Figure 3] and the tumor was freed off all its soft-tissue attachments and delivered into to [Figure 4]. The zygomatic arch was repositioned and secured. On table physiotherapy resulted in a mouth opening of 4.2 cm. Closure was performed in layers and suction drain inserted. Post-operative course was uneventful, there were no signs of any facial nerve function deficits [Figure 5] and the patient was discharged on the 3 rd post-operative day.
|Figure 5: Photograph demonstrating intact motor functions of facial nerve|
Click here to view
| Histopathology|| |
Tumor was made of fibrocartilagenous tissue along with areas of endochondral ossification. Overlying the cartilaginous tissue dense collagen fibers were noted coursing irregularly exhibiting hyalinization at focal places. The findings were suggestive of osteochondroma.
| Discussion|| |
Osteochondroma of the coronoid process causing an extraordinary pseudarthrosis joint between the coronoid and the zygoma is called as Jacob's disease.  Solitary osteochondroma is an exophytic lesion of bone that arises from the cortex and contains a prominent cap of cartilaginous tissue. Some authors have termed it as osteocartilagenous exostoses due to its differing tissue activity. Huvos AQ was of the opinion that osteochondromas occur in bones that have undergone endochondral ossification. However this theory does not satisfactorily explain the etiopathogenesis of extracondylar osteochondromas.  Lichenstein suggested that the periosteum had the pluripotent to give rise to cartilaginous and osseous cells.  Wienmann JP and Sicher H described a phenomenon in which continuous strain of tendons can result in a hyperplastic overgrowth of embryonic cells with cartilaginous potential that could correspond to osteochondromas of coronoid process. 
Kerscher A et al. proposed a theory of developmental anomaly as in most cases, the cartilage shows endochondral ossification. They presumed that osteomas of the coronoid process are sequelae of osteochondromas after total ossification of cartilage. 
However, there are certain case reports in which the osteochondromas have exhibited cellular pleomorphism of chondrocytes and disturbance of endochondral ossification. This finding is suggestive of truly neoplastic nature and has therefore been categorized as a bone tumor by several authors. 
The exact etiology of joint formation at the zygoma is not known. It has been hypothesized that the osteochondroma enlarges to compress against the zygoma. With function the zygoma resorbs and remodels resulting in a pseudojoint resulting in trismus
Continuous growth might push out the cortices of the zygoma, which might result in a malar bulge, as was evident in our case. The lesion was typical mushroom shaped and impinging on the zygoma. 
In the initial stages the patient's complaints can easily be misinterpreted as TMJ dysfunction. Careful radiographic examination followed by CT is mandatory to establish the fusion between the coronoid tumor and the zygoma. The use of bone scan, single photon emission CT can also be considered in these patients.
Various surgical approaches have been described in literature to approach the tumor. ,, In most of the moderately sized tumors intraoral coronoidectomy approach is sufficient; the larger typical mushroom shaped lesions are not amenable to this approach. The Al-Kayat Bramley approach with a modified dissection to protect the nerve is an excellent approach as it affords excellent visibility, ability to perform access osteotomy of the zygomatic arch if required and in to resection of the tumor mass. The scar is well hidden in the temporal hairline and preauricular skin crease.
At the 1 year post-operative review visit patient had adequate mouth opening [Figure 6] with no evidence of recurrence.
| References|| |
|1.||Jacob O. A rare cause for continued constriction of the jaws. Bull Mem Societe Anat Paris 1899;1:917. |
|2.||Hallam JW. Exostosis of the coronoid process of the mandible and true joint formation with zygomatic arch; case report. Br J Surg 1947;34:432. |
|3.||Hernández-Alfaro F, Escuder O, Marco V. Joint formation between an osteochondroma of the coronoid process and the zygomatic arch (Jacob disease): Report of case and review of literature. J Oral Maxillofac Surg 2000;58:227-32. |
|4.||Goudot P, Guilbert F, Buthiau D, Auriol M. Value of modern imagery in the study of coronoido-malar malformations. Apropos of 2 cases. Rev Stomatol Chir Maxillofac 1989;90:424-7. |
|5.||Van de Vyver LM. A rare restriction of mouth opening: Disease Jacob O. Acta Stomatol Belg 1962;59:187. |
|6.||Rames P, Urban F. Hyperplasia of the coronoid processes of the mandible - Case-history. Prakt Zubn Lek 1990;38:277-80. |
|7.||Lichtenstein L. Bone Tumours. 5 th ed. St Louis: CV Mosby; 1977. p. 17-29. |
|8.||Roychoudhury A, Gupta YK, Parkash H, Karak AK. Jacob disease: Report of a case and review of the literature. J Oral Maxillofac Surg 2002;60:699-703. |
|9.||Kerscher A, Piette E, Tideman H, Wu PC. Osteochondroma of the coronoid process of the mandible. Report of a case and review of the literature. Oral Surg Oral Med Oral Pathol 1993;75:559-64. |
|10.||Escuder i de la Torre O, Vert Klok E, Marí i Roig A, Mommaerts MY, Pericot i Ayats J. Jacob's disease: Report of two cases and review of the literature. J Craniomaxillofac Surg 2001;29:372-6. |
|11.||Huvos AQ. Bone Tumours: Diagnosis, Treatment and Prognosis. Philadelphia: WB Saunders; 1979. p. 139-49. |
|12.||Wienmann JP, Sicher H. Bone and Bones: Fundamentals of Bone Biology. 2 nd ed. St. Louis: CV Mosby; 1955. p. 88-126. |
|13.||Antoni AA, Brown A, Johnson JH. Osteochondroma of the coronoid process of the mandible: Report of case. J Oral Surg (Chic) 1958;16:514-7. |
|14.||Totsuka Y, Fukada H, Lizuka T, Shindoh M, Amemiya A. Osteochondroma of the coronoid process of the mandible. Report of a case showing histological evidence of neoplasia. J Craniomaxillafac Surg 1990;18:27-32. |
|15.||Ito N, Otsu T, Fujioku Y, Takeda Y, Suzuki A. Osteochondroma of the coronoid process of the mandible. Report of a case and a review of the literature. Jpn J Oral Maxillofac Surg 1981;27:863-72. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]