Year : 2009 | Volume
: 21 | Issue : 3 | Page : 122--125
Primary intraosseous carcinoma of mandible
Ankur Jethlia, Vaishali Keluskar, Arvind Shetti
Department of Oral Medicine, Diagnosis and Radiology, KLE'S V.K. Institute of Dental Sciences, Belgaum, Karnataka, India
Department of Oral Medicine and Radiology, KLE’S V.K. Institute of Dental Sciences, Belgaum, Karnataka
Primary intraosseous carcinoma (PIOC) is a rare malignant neoplasm of the jaw which is locally aggressive with poor prognosis. These tumors are believed to arise from the odontogenic epithelium and hence are referred to as odontogenic carcinomas. Till date, 47 cases have been reported in the English literature. Herein, we report a case of PIOC of mandible in a 65-year-old male patient. This article discusses the importance of detailed clinical and histological examination and review of various aspects of PIOC and updates the literature.
|How to cite this article:|
Jethlia A, Keluskar V, Shetti A. Primary intraosseous carcinoma of mandible.J Indian Acad Oral Med Radiol 2009;21:122-125
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Jethlia A, Keluskar V, Shetti A. Primary intraosseous carcinoma of mandible. J Indian Acad Oral Med Radiol [serial online] 2009 [cited 2019 Sep 20 ];21:122-125
Available from: http://www.jiaomr.in/text.asp?2009/21/3/122/58753
Primary intraosseous carcinoma (PIOC) is a very rare malignant neoplasm. Only 47 cases have been reported in the English literature till date. According to WHO classification, PIOC is an odontogenic carcinoma defined as "a squamous cell carcinoma arising within the jaw, having no initial connection with the oral mucosa, and presumably develops from the residues of the odontogenic epithelium. The definitive diagnosis of PIOC is very difficult because the lesion must be distinguished from tumors that have metastasized to the jaw from distant sites, from alveolar carcinoma that have invaded the bone from the surface, and from tumors of maxillary sinus origin.  For these reasons, case reports of PIOC are so rare. The purpose of this article is to review the literature to elucidate the clinicopathologic features of PIOC.
A 65-year-old male patient reported to the department of Oral Medicine and Radiology, KLE V.K Institute of Dental Sciences, Belgaum with a chief complaint of pain associated with swelling in right lower jaw for three months [Figure 1]. Onset of swelling was related to extraction of loose molar tooth from lower right quadrant. Swelling increased in size gradually, with rapid spurt of growth last month. His medical history was noncontributory. Patient gives history of chewing tobacco and lime for 40 years 6-7 times per day.
On extraoral examination, an oval-shaped swelling was present on right lower third of mandible measuring 3 x 3 cm in size. Swelling was extending superioinferiorly from the angle of mouth to the lower border of mandible and mediolaterally from angle of mouth to angle of mandible. Overlying skin was normal. Swelling was bony hard in consistency, tender on palpation. Right submandibular group of lymph nodes was palpable, single in number, enlarged, firm in consistency and mobile [Figure 1], [Figure 2].
Intraoral examination revealed unhealed socket with bony defect in relation to 46. Obliteration of vestibule was present with 45, 46, and 47. Grade I mobility was present with 45, 47, 48. Generalized pockets were present and oral hygiene was poor. Overlying alveolar mucosa was intact without any evidence of a mass or ulcer. There was no nerve paresthesia. Examination of head and neck region and detailed systemic examination did not reveal any abnormalities [Figure 3].
A provisional diagnosis of infected odontogenic tumor and intrabony malignancy was given and radiographic examination was carried out. Panoramic radiograph showed radiolucency with well-defined borders measuring 4 x 4 cm in size extending mediolaterally from distal aspect of 44 to distal aspect of 47, superioinferiorly from alveolar margin to 0.5 cm above inferior border of mandible. Internal structure is totally radiolucent and there is no sclerotic margin at the periphery of lesion. There is slight displacement of roots of 45 and 47. Also ill-defined mixed radiolucent radio opaque lesion is present at the apical region of 47 and up to middle third of root of 48 [Figure 4].
Incisional biopsy was advised for the patient and histological examination revealed epithelial islands of cells with dysplastic features such as hyperchromatism, pleomorphism, altered nucleocytoplasmic ratio, mitotic figures and keratin pearls formation. Loose to dense bundle of collagen fibers with proliferating plump shaped fibroblasts. Areas of degenerating bone are also seen. Dense chronic inflammatory infiltrate, endothelial lined blood vessels with RBCs, muscle and nerve bundles are seen. The above features were suggestive of intraosseous squamous cell carcinoma [Figure 5] and [Figure 6].
Primary intraosseous carcinoma (PIOC) is defined as a squamous cell carcinoma arising within the jaw bones, and has no initial connection with the oral mucosa and develops from the residues of the odontogenic epithelium (JOMS 2001). The WHO classification of PIOC includes carcinoma arising de novo, carcinoma arising from an ameloblastoma or an odontogenic cyst. 
The tumor was first described by Loos in 1913 as a central epidermoid carcinoma of the jaw.  Wills in 1948 renamed it as an intra alveolar epidermoid carcinoma. Shear modified it to primary intra alveolar epidermoid carcinoma while Pindborg in 1971 coined the term PIOC. Waldron and Mustoe later included intraosseous mucoepidermoid carcinoma as a forth type of PIOC. 
The definitive diagnosis of PIOC is often difficult as the lesion must be distinguished from alveolar carcinoma that may invade the bone from overlying soft tissues or from tumor that have metastasized to the jaw from a distant site and from primary tumor of maxillary sinus origin. 
To define a lesion in jaw as PIOC, three specific criteria's may be present: (1) histological evidence of squamous cell carcinoma, (2) absence of ulcer formation on the overlying mucosa, (3) absence of a distant primary tumor at the time of diagnosis and at least six months during the follow-up period. 
Classification of primary intraosseous carcinoma 
Type 1 : PIOC exodontogenic cyst
Type 2A : Malignant ameloblastoma
Type 2B : Ameloblastic carcinoma arising de novo exameloblastoma or exodontogenic cyst
Type 3 : PIOC arising de novo
a) Keratinizing type
b) Non Keratinizing type
Type 4 : Intraosseous mucoepidermoid carcinoma.
Squamous cell carcinoma arising de novo within the jaw bones is a very rare entity. By reviewing the English literature and excluding cases with ulceration of oral mucosa, only 47 cases of de novo PIOC were identified. 
PIOC probably develops from the remnants of odontogenic tissue; either the epithelial rests of Malassez or the remnants of dental lamina. Apart from these, remnants of salivary gland tissue and reduced enamel epithelium also contribute to the origin. The fact that PIOC seldom occurs in bones other than jaws supports the concept that PIOC is odontogenic in origin. ,
PIOC is more common in males than females (M:F-3:2) and is more frequent in the sixth and seventh decades of life. It occurs more frequently in mandible especially in posterior region than in maxilla.
Most common symptoms of patients of PIOC are pain and swelling. Sometimes, there may be complete absence of subjective symptoms in early phases and detected during routine radiographic examination. There is progressive swelling of jaws and loosening of teeth. Accelerated growth with swelling, trismus, sensory disturbances such as paresthesia and numbness can also occur with the involvement of inferior alveolar nerve. Spread to regional lymph nodes is also seen in several cases. 
PIOC presents with varied radiological features. Of the 24 cases reviewed by Kaffe et al.,  87% lesions were radiolucent and 13% mixed radiolucent-radioopaque, 61% were unilocular and 35% were not loculated. Defined, but non corticated borders, were found in 56.5% and diffuse borders in 43.5%. Root resorption and displacement were generally absent. 
The histologic features of PIOC are not pathognomonic and histologic diagnosis is often difficult. In microscopic differential diagnosis, all lesions that produce squamous epithelium must be considered. These include acanthomatous ameloblastoma, squamous odontogenic tumor, ameloblastic carcinoma, mucoepidermoid carcinoma as well as benign and malignant salivary gland tumors that present with squamous metaplasia. 
Surgical excision has been accepted as the preferred treatment modality with block dissection if lymph nodes are involved.  Other modalities such as chemotherapy and radiotherapy have been tried in non operable cases. Eighty-five percent of the cases reviewed by Zwetyenga et al. were managed by surgery with or without adjuvant radiotherapy.  Induction chemotherapy before surgery has been tried but did not provide any regression of the lesion. 
Prognosis, though difficult to determine, is speculated to be poor with two-year survival rate of 60.5%. Zwetyenga et al. reported that patients who underwent radical surgery with radiotherapy had the best prognosis with a mean survival time of 40.6 months. Two- and three-year survival rates were found to be 61.3 and 40.9%, respectively, for post surgical cases. 
The variability of the features and resemblance in clinical presentation to odontogenic cysts and tumors emphasize that PIOC should be considered in the differential diagnosis of all radiolucent lesions of jaws with persistent pain, swelling and paresthesia or numbness.  Radiographic examination is still the primary investigation in the diagnosis of PIOC. CT is also helpful, but at times CT may be non contributory, especially in patients with metallic fillings. An early diagnosis can have marked impact in the prognosis of this rare condition.
To department of Oral Pathology, KLEs V.K Institute of Dental Sciences, Belgaum.
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