Actinomycosis of the Mandible Was Suspected With Gingival Carcinoma
Actinomycosis is caused by Actinomyces israelii, and clinical features include trismus, induration, board-like mass and multiple abscesses. Actinomycosis showing the typical clinical signs has decreased with the development of antibiotics, and thus clinical diagnosis can be difficult.1) Typical infections are characterized by suppurative and granulomatous inflammation with abscesses, tissue fibrosis, and the presence of draining sinus tracts or fistulae.Actinomycosis usually spreads contiguously, ignoring tissue planes, and extruding bacteria-laden sulfur granules from erupting sinus tracts.2)Cervicofacial infection is the most common manifestation of actinomycosis, although this is generally limited to soft tissues without spreading to involve neighboring bone.An odontogenic origin is typical for cervicofacial actinomycosis, which evolves as a chronic soft tissue swelling of the sub- or paramandibular region.We report herein a case in which actinomycosis of the mandible with gingival carcinoma was suspected.
Case presentation:
A 93-year-old Japanese man with swelling of the left mandible presented with a 2-week history of swelling, pain, and purulent discharge involving the region of the left lower mandible. The lesion was 20×15 mm, appearing as an induration. Left submandibular lymph nodes showing tenderness were about 10×10 mm in size. Cytological diagnosis at the lesion was class IIIa. Computed tomography (CT) of the left mandible revealed unclear transmission images, and findings were consistent with invasion by gingival carcinoma. In addition, magnetic resonance imaging (MRI) revealed a few submandibular and supraclavicular lymph nodes. These were thus suspected to include lymph node metastases of gingival carcinoma.Histopathological examination of biopsied lesions revealed a stratified squamous epithelium allowing blood vessels to expand, and edema and infiltration of inflammatory cells. The next week, another part of the lesion was biopsied, showing inflammatory cells, granulation tissue, osteonecrosis and A. israelii. Based on these examination findings, actinomycosis was diagnosed. Subsequently, the lesion was washed with saline mixed with amoxicillin-clavulanate potassium. The subsequent clinical course has been uneventful, with no apparent signs of recurrence.
Discussion:
Actinomycosis is characterized by suppurative and granulomatous inflammation with abscesses, tissue fibrosis, and the presence of draining sinus tracts or fistulae. Since characteristic symptoms were not observed in this case, malignant tumor was strongly suggested; however, histopathological examination revealed infection with A. israelii.
Conclusion:
In summary, we present a complicated case diagnosed with actinomycosis. CT and MRI findings of destructive changes to the mandible contributed to delays in the definitive diagnosis of actinomycosis. In this case, histopathological findings were important to confirm the diagnosis.
Refference:
1). Yasuhiro Ueno, Yoshinori Jinbu, Yasuhisa Sinozaki, Mikio Kusama. A case of actinomycosis involving the lower lip, Japanese Journal of Oral & Maxillofacial Surgery,.55(1):19-21,2009.
2). Ikuro Morikawa, Shin Takemoto, Hiroshi Watanabe, Koichi Matuo, Kiichiro Yukizane. Actinomycosis Originating from Palatine Tonsil and its Diagnosis,.Otologia Fukuoka,.31(1):382-386,1985.