PIC developing from odontogenic cysts: Clinical and radiological considerations on a series of 6 cases

Abstract

Purpose

The purpose of this work is to describe the peculiarities of clinical and radiological behavior in SCCs arising from odontogenic cyst (PIOSCC).

Material & methods

Our computer based records were retrospectively reviewed looking for patients who underwent radical surgery for PIOSCC from December 2001 to January 2016 with a minimum post-operative follow-up of 2 years. Information obtained from radiological findings and treatment outcome were collected.

Results

From 2001 to 2016, 6 out of 560 SCC’s patients (1,07%) were diagnosed PIOSCC. 5 females and 1 male, mean age was 55,2 years (range, 28–82 years). 4 PIOSCC were located in the mandible while 2 in the maxilla. Orthopantomography (OPT) has not given specific signs of malignancy. CT methods (msCT/CONE BEAM-CT/contrast-enhanced CTs) provided more information: unilocular lesions with multiple and excessive cortical interruptions, periosteal reaction far beyond the lesion in all directions, dislocation or disappearance of the IAN, intense peripheral remineralization. In all cases, the treatment involved incisional biopsy of the suspect lesions and subsequent surgical excision of the primary tumor with neck dissection in continuity in the mandibular PIOSCC and in discontinuity in PIOSCC of the maxilla. Recurrence or distant metastases was not observed until now (follow-up from 48 months to 168 months)

Conclusions

Carcinomas on cysts have radiological “red flag” characteristics (bone erosion, large dimension, involvement of IAN..) that must be taken into consideration in order to perform an early diagnosis and a correct treatment. Accurate radiological study can reduce misdiagnosis and improper treatment. PIOSCC have a progression of the disease and a different prognosis from real intraosseus carcinomas (PIC) and although it is a rare entity it must be considered in the differential diagnosis of larger osteolytic lesions.

Highlights

  • We described the peculiarities of clinical and the radiological behavior in some SCCs arising from an odontogenic cyst (PIOSCC) treated, in order to characterize the aspects useful for a correct diagnosis of this rare kind of tumor which have a progression of the disease and a different prognosis from real intraosseus carcinomas (PIC).

  • A in-depth radiological study may allow an early diagnosis and can avoid the accidental removal of carcinomas on cysts and then the neoplastic diffusion.

Introduction

Primary odontogenic intraosseous carcinoma is a rare malignant lesion affecting the jaw bone [ ]. The aetiology seems to be related to the malignant degeneration of embryological remnants. Epithelial rest of Malassez, dental lamina and dental follicle epithelium represent potential suspects [ ].

Its nomenclature and definition have changed over time: “intraosseous epidermoid carcinoma” [ ],” primary intraosseous odontogenic carcinoma” [ ], “primary intraosseous squamous cell carcinoma” (PIOSCC) [ , ].

The former WHO classification (2005) that divided PIOSCC into 3 subtypes (solid, originated from a cyst or associated with other benign epithelial odontogenic tumors) has been revised: actually primary intraosseous carcinoma (PIC) appeared in the 4th edition of the World Health Organization Classification of Head and Neck tumors as a single diagnostic entity in 2017 [ ].

Despite the few cases described in the literature (about 250 cases), SCCs arising from an odontogenic cyst have their own clinical and radiological peculiarities distinct from the solid intraosseous carcinomas. Furthermore, there is a lack of literature on this type of pathology.

The purpose of this work is to describe the peculiarities of clinical and radiological behaviour in a serie of cases treated at our institution, in order to characterize the aspects useful for a correct diagnosis.

Materials and methods

The authors retrospectively reviewed the records of patients who underwent radical surgery for PIOSCC from December 2001 to January 2016 with a follow-up of at least 2 years.

This study was approved by the independent ethics committee of the author’s hospital.

Tumor stage was classified according to the TNM classification of the International Union Against Cancer (AJCC) [ ] and histologic differentiation according to the WHO classification [ ].

The diagnostic criteria of primary intraosseus odontogenic squamous cell carcinoma (PIOSCC) included the absence of a primary lesion of the overlying mucosa or skin and the exclusion of metastasis from a distant primary site. Moreover cases of the solid type of intraosseus cell carcinoma (PIC) were excluded from the study.

All patients underwent extensive pre-operative evaluation (Orthopantomography, msCT, CBCT, CT with contrast, and in selected cases MRI). Information obtained from radiological findings were collected and thoroughly evaluated.

Results

Patient characteristic

The clinicopathological characteristics of the patients are presented in Table 1 . In the period from 2001 to 2016, 6 of 560 patients (1,07%) were diagnosed PIOSCC. (5 females and 1 male). The mean age was 55,2 years (range, 28–82 years) (see Table 2 ).

Table 1
Clinical Characteristic of 6 patients with pioscc
N age gender primary site chief complaints previous hypothesis treatment before diagnosis duration after treatment (mo) Hystology
1 28 female maxillary molar and sisus – swelling
– pain
– sensory disturbance area infraorbitary nerve
– nasal obstruction
residual cyst tooth extraction
FESS
3 PIOSCC well differentiated
2 40 female mandible angle-angle-ramus – swelling
– pain
– sensory disturbance area of the NAI
TMJ problems
infected follicular cyst
MRI TMJ cystectomy 6 PIOSCC well differentiated
3 52 female mandible angle-ramus – swelling
– pain
– sensory disturbance area of the NAI
infected follicular cyst cystectomy with fracture of the mandible 3 PIOSCC moderately differentiated
4 57 male mandible ramus – swelling
– pain
– sensory disturbance of the NAI
residual cyst tooth extraction and cystectomy 3 PIOSCC moderately differentiated
5 82 female mandible angle-ramus – swelling
– pain
– oro-cutaneus fistula
teeth infection extraction and fistula closure 12 PIOSCC moderately differentiated
6 72 female maxillary molar and sinuses – swelling
– sensory disturbance infraorbital nerve
– nasal obstruction
infected radicular cyst extraction 6 PIOSCC well differentiated

Table 2
Radiological characteristic of 6 patients with pioscc
N age gender primary site radiologic findings (panoramic) MRI Radiologic findings (MSCT or CBCT) Radiologic findings CT with contrast
1 28 female maxillary molar and sisus radiolucent lesion (Hypothesis residual cyst) no bony erosion the sinus e xpansive lesion with parenchymatous appearance, poorly vascularized, with a maximum diameter about 3 cm with calcifications inside
2 40 female mandible angle-angle-ramus voluminous radiolucent lesion of the left mandibular ramus with an impacted 3.8 tooth (hypothesis follicular cyst) alteration of the signal: irregular inhomogeneous hypointensity in the T1-weighted sequences and irregular hyperintensity in the weighted T2-STIR sequences expansive lesion with widespread periosteal reaction, extensive peripheral reminemeralization and cortical disruptions tissue with intense and irregular enhancement, widely involving the left in infratemporal fossa
3 52 female mandible angle-ramus radiolucent lesion in the right mandibular ramus in correspondence with the crown of 4.8 included (hypothesis follicular cyst) no osteolytic lesion, 3 cm in his maximum diameter
interruption of the cortical bone areas of peripheral remineralization
involvement of the NAI channel
tissue with intense and irregular enhancement, widely involving the right masseter e medial pterigoid muscle
4 57 male mandible ramus radiolucent lesion in the right mandibular ramus (hypothesis residual cyst) no expansive lesion in the right mandibular body with a larger size of 3 cm
Interruption of the cortical bone
Areas of peripheral remineralization Involvement of the NAI
perimandibilar tissue with intense and irregular enhancement, widely involving the right masseter e myloyd muscle
5 82 female mandible angle-ramus radiolucent lesion in the right mandibular ramus in correspondence with 3.8 included (hypothesis residual cyst) no expansive lesion in the right mandibular body with a larger size of 4 cm
Interruption of the cortical bone
Involvement of the NAI
tissue with intense and irregular enhancement, widely involving the right masseter e medial pterigoid muscle
6 72 female maxillary molar and sinuses radiolucent lesion (Hypothesis residual cyst) alteration of the signal: irregular inhomogeneous hypointensity in the T1-weighted sequences and irregular hyperintensity in the weighted T2-STIR sequences, bony erosion the sinus solid lesion involving the alveolar process at the maxillary level that determines root wear, thinning of the maxillary corticals. its occupied a good part of the maxillary sinus and is surrounded by thin calcified walls. the radiological finding is suspect due to a neo-productive intracistic lesion

Four PIOSCC were located in the mandible and 2 were located in the maxilla.

The main complaints included swelling, pain, pathological fracture and sensory disturbance of the region in the IAN or infraorbitary nerves territory. In maxillary lesions nasal obstruction symptoms were sometimes present.

In all the cases, the primary diagnostic hypothesis was different from that of a cancerous cyst. The previous hypotheses were of infected residual cysts for the two maxillary cases (cases 1 and 6). In the mandibular localizations, the hypotheses prior to the final diagnosis were of complicated and infected follicular cysts (cases 2 and 3) and of infected residual cysts (case 4). The case n°5 was diagnosed and treated at an other institution as a cutaneous fistula secondary to a dental abscess. In this last case, radiological investigations had not been performed and a plastic of the fistula had been attempted three times.

All the reported cases had incongruous diagnosis and interventions before the definitive diagnosis (dental extractions, FESS, cystectomies with an iatrogenic fracture of the jaw, extraction of teeth included and corrections of cutaneous fistula. The average diagnostic delay was 5.5 months since the onset of the symptomatology (from 3 months to 12 months as extreme).

Radiodiagnostic characteristics

Orthopantomography (OPT) has not given specific signs, which differentiate cystic lesions from cancerous cystic lesions. Only in three cases (case 2, case 3 and 5), we could detect the lack of sclerotic edge typical of odontogenic cysts. From this type of examination, it appears difficult to strap down further significant or specific data ( Fig. 1 ).

Mar 3, 2020 | Posted by in Oral and Maxillofacial Surgery | Comments Off on PIC developing from odontogenic cysts: Clinical and radiological considerations on a series of 6 cases
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