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An Official Publication of the Indian Association of Oral and Maxillofacial Pathologists

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Year : 2023  |  Volume : 27  |  Issue : 5  |  Page : 45-51

Actinomycosis of parotid gland after maxillary molar extraction, case report and review of literature

Pathology Department, Health Sciences University, Umraniye Training and Research Hospital, Elmalikent Mahallesi, Adem Yavuz Bulvarı, No: 1, Posta Code: 34766, Umraniye/Istanbul/, Turkey

Date of Submission12-Jun-2022
Date of Decision14-Jun-2022
Date of Acceptance15-Sep-2022
Date of Web Publication04-Feb-2023

Correspondence Address:
İrem Guvendir
Health Sciences Unversity, Umraniye Education and Training Hospital, Pathology Department, Elmalikent Mahallesi, Adem Yavuz Bulvarı, No: 1, Posta Code: 34766, Umraniye/Istanbul
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jomfp.jomfp_257_22

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Although actinomycosis is frequently seen in the cervicofacial region, it is very rare in the parotid gland. Furthermore, it can be confused with salivary gland malignancies in imaging. The most important underlying causes are cervicofacial trauma, tooth extraction history and poor oral hygiene. A 43-year-old male patient was admitted to otorhinolaryngology department with a complaint of progressive swelling on his cheek. The histopathological examination of fine-needle aspiration (FNA) biopsy showed acute suppurative polymorphous leukocytes and actinomycese hyphae balls within histiocytes. The patient was started on amoxicillin 2 gm per day for two months. With antibiotherapy, the swelling in the patient's parotid gland decreased and completely healed at the end of six months. Primary parotid actinomycosis has been rarely reported in the literature, differential diagnosis is usually problematic as both clinical and radiological findings may mimic parotid tumour; however, it can be useful to apply FNA cytology for a quick diagnosis and treatment.

Keywords: Actinomycosis, cytology, fine needle aspiration, parotid gland

How to cite this article:
Guvendir &, Karabulut MH, Zemheri IE. Actinomycosis of parotid gland after maxillary molar extraction, case report and review of literature. J Oral Maxillofac Pathol 2023;27, Suppl S1:45-51

How to cite this URL:
Guvendir &, Karabulut MH, Zemheri IE. Actinomycosis of parotid gland after maxillary molar extraction, case report and review of literature. J Oral Maxillofac Pathol [serial online] 2023 [cited 2023 Mar 24];27, Suppl S1:45-51. Available from: https://www.jomfp.in/text.asp?2023/27/5/45/369172

   Introduction Top

Actinomyces species are members of the normal oral flora and may rarely cause cervicofacial infection. Actinomycosis is an opportunistic infection caused by gram positive anaerobic bacteria of the Actinomyces spp., commonly A. Israelii.[1] It affects mainly the cervicofacial (50%), abdominopelvic (20%), thoracic (15%) regions and rarely the central nervous system (2%).[2]

Actinomycosis of the parotid gland is quite rare, and only a few cases have been reported in the literature since Leonarmand first reported it in 1913.[3] It may clinically and radiologically be confused with malignancies, tuberculosis, epidermoid cyst, other fungal infections and bacterial abscesses. Infection usually develops where the integrity of the oral mucosa is impaired, due to local trauma, tooth extraction, gingival surgery or poor oral hygiene.[1] The definitive diagnosis depends on microbiological and histopathological examination. H&E can be used in fine-needle aspiration (FNA) biopsy for diagnosis, and gram staining is useful to identify actinomyces[4],[5] Current recommended treatment regime for actinomycosis is high-dose benzylpenicillin or amoxicillin for up to three or four months.[1]

Our aim is to emphasise the importance of FNA cytological examination in the approach to parotid masses and to present the diagnosis and treatment methods of the patient by comparing it with other cases in the literature.

   Case History Top

A 43-year-old male patient was admitted to otorhinolaryngology department with a complaint of progressive swelling on his right cheek and accompanying pain and tenderness with palpation [Figure 1]. He reported neither any fever, cough nor difficulty in chewing or breathing. Patient didn't have any chronic disease, immune suppression, history of diabetes mellitus and any substance/drug use except for smoking tobacco (20 packs/year). The mass started as a small swelling after a molar tooth extraction three months ago and further grew. On physical examination, there was a fixed, firm mass with a diameter of 4 cm filling the parotid gland and an accompanying 2 cm lymph node at right submandibular region. Oral hygiene was poor. The oropharynx and indirect laryngoscopic examinations were normal. Mouth opening was not restricted and there were no signs of facial nerve palsy. Laboratory assessment revealed normal white blood cell count while C reactive protein (CRP) was 57 mg/L and sedimentation rate was 81 mm/h both of which were quite high. Tuberculosis, hydatid cyst (both endemic in the region) and HIV were ruled out with appropriate serological tests and imaging studies. Ultrasonography of the mass showed a complex septated cystic lesion and hypoechoic solid component (45 × 22 × 38 mm) in the right parotid gland with indistinguishable borders that can hardly be differentiated from the adjacent parenchyma. Magnetic resonance imaging (MRI) studies of the cervical region revealed a T1 hypointense [Figure 2] – T2 hyperintense [Figure 3] lesion localised in the right masseter muscle extended to the parotid gland with a cystic component in the middle and without any signs of destruction in the adjacent bone structures.
Figure 1: Photograph of the patient after FNAB procedure

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Figure 2: On MRI scan T1 sequences, hypotense, centrally cystic lesion with intense contrast enhancement at the periphery. No destruction was observed in bone structures in the sequences

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Figure 3: On MRI scan, hyperintense appearance of the lesion on T2 sequence, viewed from the right

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FNA was performed on the patient. After the material from the needle was spread on the slides, a cell block was obtained from the remaining tissue particle; slides stained with Pap, and cell block sections were stained with haematoxylin–eosin (H&E) and periodic acid-Schiff (PAS) in the pathology laboratory. The histopathological examination of fine-needle aspiration cytology (FNAC) revealed intense acute suppurative polymorphous leukocytes and actinomyces hyphae balls within histiocytes in H&E [Figure 4] and PAS [Figure 5] staining. Actinomycosis balls and hyphae were seen as a result of FNAC performed together with physical examination, ultrasound findings and MRI imaging, and the patient was diagnosed with actinomycosis of the right parotid gland. Infectious diseases were consulted urgently for the patient and he had diagnosed with actinomycosis of the parotid gland. The patient was started on amoxicillin 2 gm per day for two months under infectious disease consultation. During follow-up with anti-biotherapy, the swelling of the parotid gland was decreased and completely healed at the end of six months.
Figure 4: Actinomycese balls in a suppurative background in the cell block under the light microscope (4X, H&E)

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Figure 5: Bacterial filaments at the periphery of actinomyces balls in the light microscope (40X, PAS)

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   Discussion Top

Actinomycosis is caused by bacteria of the Actinomyces spp., most commonly A. Israel and A. gerencseriae in humans.[1] Although it is most commonly seen in the cervicofacial region (50%), it is observed in the abdominopelvic (20%), thoracic (15%) and central nervous systems (2%), respectively.[2]

These bacteria are not normally pathogenic, but can cause an opportunistic infection when the mucous membrane is punctured by local trauma, typically following tooth extraction or maxillofacial surgery. Tooth extractions, particularly mandibular molar extractions, are considered the leading cause of cervicofacial actinomycosis.[6] Actinomycosis progression is also associated with poor oral hygiene, diabetes, immunosuppression, radiotherapy, bisphosphonates, smoking, and alcoholism.[7],[8] Our patient had a history of maxillary molar tooth extraction three months ago and had smoked 20 packs/year.

Actinomycosis is rarely seen in the cervicofacial region and only a few cases of parotid actinomycosis have been reported in the literature [Table 1]. As can be seen from the table, actinomycosis in the parotid gland has a presentation that mimics malignancy by growing in the gland. FNA before the surgical procedure is effective in making the absolute diagnosis and preventing further surgery. Since, if a definitive diagnosis is made, appropriate treatment can be applied easily.
Table 1: Cases of actinomycosis of the parotid gland in the English Literature

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Actinomycosis of the parotid gland may mostly present as a slow-growing mass, or with an acute, suppurative, painful and feverish course.[1] In clinical approach, the differential diagnosis of parotid gland mass includes benign or malignant neoplasia, epidermoid cyst and  Mycobacterium tuberculosis Scientific Name Search fection.[9],[10] As the mass lesion progresses, a cutaneous fistula may develop spontaneously or may be triggered after an FNA.[3]

During clinical evaluation of bilateral parotid enlargement, the diagnoses to be considered are sialadenitis, sialolitiasis; infections caused by viral (mumps, HIV); mycobacterial (M. tuberculosis); bacterial agents (acute suppurative parotitis); neoplastic lesions like Warthin tumour, malt lymphoma, oncocytoma; and autoimmune diseases, including Sjögren, Wegener's granulomatosis and sarcoidosis.[11] When there is unilateral enlargement in parotid, sialadenitis, sialolitiasis, lymphoma, metastatic lymphadenopathy, benign neoplasms and primary parotid malignancies should be considered at the first place for differential diagnosis.[5] In our case, the unilateral enlargement of the parotid gland was not accompanied by fever, the progression of mass was slow and there was no pain with chewing. Thus we excluded the diagnosis of sialedinitis on the foreground. While the absence of bilateral involvement reduced the possibility of viral agent in the aetiology, the fact that the patient was male, had no other accompanying systemic findings, and he had unilateral parotid mass excluded autoimmune diseases such as Sjögren's disease and sarcoidosis. Even though neoplastic processes have unilateral involvement in the parotid, the patient's good general health, absence of alarm symptoms such as weight loss, anaemia and night sweats, and preservation of oral-facial functionality clinically excluded malignant tumours in particular. Poor oral hygiene, history of recent tooth extraction and the presence of ipsilateral palpable lymph nodes may suggest a clinical diagnosis of subacute bacterial infection, possible abscess formation or M. tuberculosis infection (especially in an endemic region). Further radiological and histopathological examinations were necessary to establish the final diagnosis.

Primary parotid actinomycosis has been rarely reported in the literature, and differential diagnosis is usually problematic as both clinical and radiological findings may mimic parotid tumour.[9] It may not be easy to distinguish parotid actinomycosis from malignancy also with radiological imaging methods such as computed tomography (CT), US, MRI, positron emission tomography.[3] However, findings are suggesting soft tissue or bone infiltration in CT scanning, mimicking malignant neoplasm, may help to distinguish actinomycosis from other suppurative and granulomatous masses.[4],[12] In our case, the presence of a cystic component of the lesion in the MRI and the fact that the lesion did not infiltrate the adjacent bone structure suggested a benign lesion in the first place. Thus in differential diagnosis, the possibility of a neoplasia (such as cystadenoma and Warthin tumour as benign; adenoid cystic carcinoma, carcinoma ex pleomorphic adenoma and mucoepidermoid carcinoma as malignant) which may have a cystic component should not be overlooked. Histopathological examination is important to clarify the definitive diagnosis among this wide range of possible neoplastic lesions.

FNAC and/or tissue biopsy should be performed for a definitive diagnosis.[9] The culture of the sample from FNAC or tissue biopsy usually gives a negative result due to the difficulty in maintaining anaerobic culture conditions. However, it is diagnostic to see filamentous bacterial clusters in suppurative inflammation with the naked eye in H&E stained preparations in light microscopic examination.[9]

In the diagnosis, histopathological examination contains yellowish sulphur granules in approximately one-third of the cases. On H&E, they appear as basophilic masses with eosinophilic terminal ends and as balls of bacterial clumps with filaments. Granules in the periphery of the filaments can also be shown by gram staining.[8] Extensive, suppurative neutrophils and plasma cells can be observed around the actinomyces hyphae balls on examination. It may form granulomas with histiocytes; therefore, infections such as granulomatous tuberculosis, cat-scratch disease, syphilis, leprosy and other bacterial and fungal-induced pyogenic abscesses should be excluded in the differential diagnosis.[13] In our case, actinomyces hyphae were clearly seen in the cell block obtained from FNA in both H&E and PAS stained preparations [Figure 3].

Complications such as bleeding, inflammation, and parotid gland infarction during the parotid FNAC procedure may accelerate the spread of actinomyces through seeding.[14] Even though it is invasive, FNAC of the parotid is fast, inexpensive, practical and the most effective method for definitive diagnosis.

In treatment, high-dose benzylpenicillin and amoxicillin are recommended. A daily dose of 20 million IU IV or IM benzylpenicillin is used. In the treatment of oral amoxicillin, the recommended doses are between 2 gm and 4 gm per day. The duration of treatment may be variable among different centres but a In addition to penicillin, inhibitors of β-lactamase 5 (eg, clavulanic acid) can be used for other bacterial pathogens due to the development of polymicrobial infection.[1],[8] For our patient, it was decided to use amoxicillin for two months in consultation with the department of infection.

Surgical debridement or drainage of the abscess may be necessary to benefit antibiotic penetration.

Although the enlargement of the parotid gland due to actinomycosis infection is quite rare, it should be kept in mind if the patient has a history of orofacial trauma. The definitive diagnosis can be made very quickly and accurately with FNA cytology.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


Dr. Irem Guvendir: Writing - Original Draft. Dr. Murat Hakan Karabulut: Review and Editing. Dr. Itir Ebru Zemheri: Supervision.

Clinical implication

Actinomyces species may rarely cause cervicofacial infection but more rarer in parotid gland. Symptoms can imitate a tumour of parotid gland, therefore clinicans and pathologists should be aware.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Vandeplas C, Politis C, Van Eldere J, Hauben E. Cervicofacial actinomycosis following third molar removal: case-series and review. Oral Maxillofac Surg 2021;25:119-25.  Back to cited text no. 1
Miller M, Haddad AJ. Cervicofacial actinomycosis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85:496–508.  Back to cited text no. 2
Lee DH, Jung EK, Lee JK, Lim SC. Actinomycosis of the parotid gland: Case series. Ann Palliat Med 2021;10:6062-6.  Back to cited text no. 3
Varghese BT, Sebastian P, Ramachandran K, Pandey M. Actinomycosis of the parotid masquerading as malignant neoplasm. BMC Cancer 2004;4:7.  Back to cited text no. 4
Ulvi BM. Actinomycosis of the parotid gland. Plast Reconstr Surg 2005;115:659-61.  Back to cited text no. 5
Pulverer G, Schutt-Gerowitt H, Schaal KP. Human cervicofacial actinomycoses: Microbiological data for 1997 cases. Clin Infect Dis 2003;37:490-7.  Back to cited text no. 6
Kaplan I, Anavi K, Anavi Y, Calderon S, Schwartz-Arad D, Teicher S, et al. The clinical spectrum of Actinomyces-associated lesions of the oral mucosa and jawbones: Correlations with histomorphometric analysis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108:738-46.  Back to cited text no. 7
Valour F, Sénéchal A, Dupieux C, Karsenty J, Lustig S, Breton P, et al. Actinomycosis: Etiology, clinical features, diagnosis, treatment, and management. Infect Drug Resist 2014;7:183-97.  Back to cited text no. 8
Sittitrai P, Srivanitchapoom C, Pattarasakulchai T, Lekawanavijit S. Actinomycosis presenting as a parotid tumor. Auris Nasus Larynx 2012;39:241-3.  Back to cited text no. 9
Dubey A, Murthy JG, Banerjee PK. Actinomycosis of the parotid gland. Indian J Otolaryngol Head Neck Surg 2004;56:306-8.  Back to cited text no. 10
Chen S, Paul BC, Myssiorek D. An algorithm approach to diagnosing bilateral parotid enlargement. Otolaryngol Head Neck Surg 2013;148:732-9.  Back to cited text no. 11
Mamais C, Dias A, Walker J, Vydianath SR. Parotid actinomycosis mimicking metastatic lymphadenopathy. West Indian Med J 2011; 60:349-50.  Back to cited text no. 12
Nwawka OK, Nadgir R, Fujita A, Sakai O. Granulomatous disease in the head and neck: developing a differential diagnosis. Radiographics 2014;34:1240-56.  Back to cited text no. 13
Nayak L, DiMaio M, Jeffrey RB. Extraglandular extension of parotid actinomycosis after sonographically guided fine-needle aspiration. J Ultrasound Med 2013;32:715-6.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1]


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