Primary intraosseous oral squamous cell carcinoma (PIOSCC) of the jaws: two clinical cases

OBJECTIVES The aim of this paper is to provide an overall picture of primary in traosseous squamous cell carci noma (PIOSCC) from a clinical and radiographical point of view, ana lyzing the diagnostic and thera peutic process through the de scription of two clinical cases. MATERIALS AND METHODS PubMed, Google Scholar, Scopus, and Embase databases were con sulted, and the key words “primary intraosseous squamous cell carci noma,” “intraosseous carcinoma of the jaws,” and “odontogenic keratocyst” were used for the re search. Case reports, case series, and systematic reviews of the liter ature were included. Moreover, we also discuss two clinical cases re ferred to the department of the au thors (ASST Santi Paolo Carlo S.C. Odontostomatology II, Milan, Italy) for a mandibular swelling with no alterations affecting the overlying mucosa. RESULTS Considering the rarity of PIOSCC, in both cases it was necessary to col lect complete medical history, add radiographic data to the clinical ex amination and perform an incision al biopsy in order to reach a defini tive diagnosis. The surgical removal of the lesion, followed by adjuvant radiotherapy (RT), was the first choice treatment for both patients. CONCLUSIONS Primary intraosseous squamous cell carcinoma (PIOSCC) is a rare malignant neoplasm that lacks an initial connection with the oral mucosa. It can arise de novo from remnants of odontogenic epithelium or from the epithelial layer of odontogenic cysts or keratocysts. More common in the lower jaw (79%) rather than in the maxilla (21%), its preferential site is the posterior region of the mandible (retromolar and ramus areas). It preferentially affects adult males, with a mean age of 57.3 years and a range that can vary from 5 to 89 years. The prognosis of primary intraos seous squamous cell carcinoma is poor: in fact, the local recur rence rate is around 20% and the 5-year survival rate is between 30 and 40%. The recommended treatment is the surgical resection of the le sion, together with elective neck dissection. Adjuvant radiothera py and chemotherapy may be evaluated according to the fea ture of the clinical case. CLINICAL SIGNIFICANCE Due to the lack of pathognomonic clinical signs, the diagnosis of PIOSCC still remains a complex process. The clinical and radio graphic appearance, especially in the early stages and when the tu mor is small in size, may be almost entirely superimposable to the clinical features of odontogenic cysts or other benign neoplasms. The rarity of this malignancy and the presence of nonspecific signs and symptoms often lead to a wide diagnostic delay, which can range from few weeks up to 18 months.