Multimodality imaging of cervicofacial actinomycosis

Yoi. 75 No. 6

Deter

RADIOLOGY

Multimodality

imaging of cervicofacial actinomycosis

Banna Sa’do, DDS, PhD,a Kazunori Yoshiura, DDS, PhD,a Kenji Yuasa, DDS, PhD,a Yoshiko Ariji, DDSa Shigenobu Kanda, DDS, PhD,a Masuichiro Oka, MD, PhD,b and Takeshi Katsuki, DDS, PhD,C Fukuoka, Japan KYUSHU

UNIVERSITY

AND

SAGA

MEDICAL

COLLEGE

Actinomycosis is an uncommon rhronic disease usually caused by Actinomycesisraelii It affects the soft tissue mainly but sometimes spreads to involve salivary glands, bone, or even the skin of the face and neck. Five cases have been seen in our department. Several imaging modalities were used to assist in making the diagnosis. The cases are presented and the literature reviewed. Ultrasonography was found to be a useful diagnostic tool especially in developing the differential diagnosis. (ORAL SURG ORAL MED ORAL PATHQL 19!93;76:772-82)

Actinomycosis is a chronic disease caused mainly by the anaerobic, gram-positive organism, Actinomyces israelii.’ Swelling and induration of the soft tissue are the most common symptoms. When the infection spreads to bone, bone destruction is likely to 0ccur.l’ 2 The disease is usually diagnosed on microbiologic or histologic examination. However, when the clinical symptoms are not typical, it may be misdiagnosed as a tumor.3 Therefore a reliable diagnostic method is required. The disease was well documented in the literature. In most of the reports, the diagnosis was based on microbiologic or histologic findings, although some were based primarily on clinical findings.4 In just a few reports, sialography,5* 6 computed tomography (CT),7-9 or radionuclide imaginglo were used. No documentation with respect to ultrasonography (US) was found. Five cases of actinomycosis have been seen in our department. Several imaging modalities were used including ultrasonography. As some of our expressions might not be familiar to the general dentists, we would like to explain these in advance. ‘Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Kyushu University. bSecondDepartment of Oral and Maxillofacial Surgery, Faculty of Dentistry, Kyushu University. CDepartment of Oral and Maxillofacial Surgery, Saga Medical College. Copyright @ 1993 by Mosby-Year Book, Inc. 0030-4220/93/$1.00 + .lO 7/16/47557 772

On ultrasonograms, we usually evaluate the masses, nodules, etc. in comparison with the adjacent healthy parenchyma for the definition of hypo-, iso-, or hyperechogenicity. We call a mass hypoechoic if it has a intensity lower than that of the adjacent tissue. Hyperechoic is used for masses of higher intensity and isoechoic for masses with a intensity similar to the adjacent tissue. The appearance of hypoechoic masses is darker whereas the hyperechoic masses appear rather brighter, and the isoechoic ones have a similar appearance to that of the adjacent tissue On CT scans and magnetic resonance (MR) imaging, the category is made up in comparison with the muscle. The criterion is almost the same with the use of the expressions low, iso-, and high density for CT scans; low, iso-, and high intensity/signal intensity for MR imaging. CASE REPORTS

Table I summarizes the signs and symptoms of the five casesat time of examination. Table II shows the devicesand the materials that were used in the evaluation. Case 1

Five months before admission to our hospital, a 47-yearold woman had a painless swelling in the right submandibular area. She visited her dentist who administered antihiotics for 2 weeks, after which the swelling disappeared. Two months later, she returned with a mass in the same area. Her

dentist diagnosed pericoronitis and extracted the right inferior third molar. For a time the mass got smaller. However, a month later she suffered from sudden pain with a swelling of the same area. The pain disappeared within 2

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Table I. Summary oiFthe five cases Location

Case

Submandibular gland, right side Parotid gland, right side

1

41/F

2

54/M

3

73/F”

Parotid gland, right side

4

65/F

Temporomandibular joint, right side

5

56/F

Parotid gland, right side

signs Clinical symptoms

and Working diagnosis

Remarkable swelling, complaint free. Spontaneous and biting pain, remarkable swelling, induration of the region, trismus. Oppressive pain, remarkable swelling, induration of the cheek, redness, and local fever. Trismus, displacement of the mandible to the left. Remarkable swelling, induration of the cheek, redness, and local fever.

1 Applied imaging modalities

Pleomorphic adenoma

US, sialography

Tumor of the gland

US, sialography, CT

Arthrosis of TMJ, tumor of the parotid gland

US, sialography, CT

Inflammation of the right TMJ and surrounding area Tumor of the gland

US, sialography, CT, MRI US, sialography, CT

*Patient had a history of rheumatism.

Table II. Apparatus and materials that were used in the imaging evaluation Modal&J

Apparatus or materials

Computed tomalgraphy Ultrasonography Sialography (Sialo) Screen film system Contrast medium

Somatom Dr U-sonic model RT-2600

Magnetic resonance

Manufacturer

Remarks

Siemens, Erlangen, Germany Yokogawa Medical Systems, Tokyo

4 mm-thick axial and coronal scans 7.5 MHz transducer Film focus distance 100 cm

Min-R System

Eastman Kodak Co., Rochester, N.Y.

Omnipaque 350

Daiichii Seiyaku Co., LTD, Tokyo

Urografin 76% MRP-20-2

Schering AG, Berlin

Hitachi Medico, Tokyo

weeks but the swelling did not. Her dentist referred her to

the second Department of Oral and Maxillofacial surgery in our hospital, and she was referred to our department

(Radiology) with an initial diagnosis of pleomorphic adenoma of the right submandibular gland. Sialography was performed on the right submandibular gland. The Wharton’s duct appeared enlarged, and the gland itself was mottled. Pooling of the contrast medium was detected in the middle part of the gland, and a filling defect seen in the lower posterior portion (Fig. 1, A). US revealed a hypoechoic area in the submandibular gland. The area had an ill-defined margin with a hyperechoic spot seen in the lower part (Fig. 1, B). With the patient under general anesthesia, the right submandibular gland was resected. The patient is doing fine.

0.2 T

and masseter areas. A few days later, induration of the area concomitant with trismus became apparent. CT-sialography revealed a low density area in the external side of the right ramus, the surface of the bone was rough (Fig. 2, A and B). The result of the sialography was normal. However, because of the pressure of the soft tissue mass on the gland itself, a pseudofilling defect was noticed in the lower portion (Fig. 2, C). US showed a hypoechoic area on the surface of the ramus. This area had an ill-defined margin with hyperechoic spots in the lower part (Fig. 2, D and E). Case 3 A 73-year-old woman was referred to our department by the Department of Oral and Maxillofacial surgery, Saga

Medical College for radiologic imaging. The patient had a Case 2 Two weeks blefore being referred to our department, a 54-year-old man had a movement of the inferior right first molar, accompanied with spontaneous and biting pain. The second day, he had a swelling that extended to both parotid

swelling in the right parotid area for a week. Results of her blood analysis were within normal limits. Therefore a tumor of the parotid gland was expected. Several “punched out” radiolucencies were seen in the cortical bone of the right ramus on the panoramic radio-

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Fig. 1. A, Sialography of submandibular gland (posteroanterior view). Notice pooling of contrast medium. indicates filling defect of medium. B, Hypoechoic, ill-defined mass was detected by US. Note hyperechoic spot (arrow). Diagram shows interpretation of ultrasound image and position of imaged tissues.

Arrow

graph (Fig. 3, A). CT scans revealed a soft tissue density mass that extended to the masseter muscle, the parotid gland, and the internal pterygoid muscle. A defect of the external cortical surface of the ramus was also noticed (Fig. 3, B and C). However, no osteolytic bone marrow changes were seen. Sialography of the parotid gland revealed the punctate pattern of the peripheral ducts (thought to be a result of a history of rheumatism) with pooling of the contrast medium detected in the lower part of the gland (Fig. 3, D). US showed heterogeneous hypoechoic area with an ill-defined margin. The linear pattern of bundles of the masseter muscle was noticeable. No boundaries between the

mass and either the parotid gland or masseter muscie could be seen (Fig. 3, E). Case 4 A 6%year-old woman had a pain in the upper right molars area for 7 months before being admitted to our hospital. Because of the pain, her dentist extracted the first molar after administering antibiotics for 1 week. A month later, a swelling of the area concomitant with pain and displacement of the mandible to the left became apparent. She had been admitted to several other hospitals, and surgical draining was performed together with the administration of

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Fig. 2. A, CT-sialography shows low density area in external side of right ramus (arrow). Note swelling of masseter and medial pterygoid muscle. Displacement of parotid gland laterally can be seen as well. B, Arrows indicate cortex destruction. C, Normal sialography. Arrow indicates pseudofilling defect.

antibiotics. Five months later, she suffered of trismus and severe displacelment Iof the mandible. One month later, she was admitted tsothe second department of Oral and Maxillofacial Surgery of our university. An MRI of the patient showed an area of hyperintensity around the condylar process and a bright signal from the masseter muscle (Fig. 4, A). CT revealed cortex resorption of the right condyle (Fig. 4, B). No osteolytic bone marrow changes were seen. The masseter and pterygoid muscles were thickened, which make the fat space of the masticator space disappear (Fig. 4, C). Moreover, a low density diffused area was detected on the internal surfasce of the masseter (Fig. 4, D). On US this was a diffuse hypoechoic area (Fig. 4, E). Case 5 A 56-year-old woman had a painless mass in the right parotid gland alrea for 8 months. Later the patient developed trismus that made her consult her dentist who referred her to our hospital. A tumor of the parotid gland was suspected,

therefore the patient was referred to our department for radiologic examination. Several “punched-out” radiolucencies were seen in the right mandible in the molar area and at the angle. These were accompanied by sclerotic bony change (Fig. 5, A). CT scans supported these findings (Fig. 5, B) and showed enlargement of the masseter muscle. A soft tissue structure was detected in the right perimandibular area (Fig. 5, c). A hypoechoic, irregular structure that extended between the masseter muscle and the submandibular area was detected on the ultrasonogram. Destruction of the cortex was also seen (Fig. 5,O). However, no osteolytic bone marrow changes were visible. Sialography of the parotid gland was normal except for a pseudofilling defect as a result of the pressure of the mass. A surgical incision was performed in the last four cases. Pus mixed with sulfur granules was discharged. Bacampicillin (BAPC) was administered for periods that ranged between 3 and 5 months, and patients are symptomfree.

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Fig. 2. cont’d. I) and E, IIypoechoic, ill-defined massdetected on US. Note hyperechoic spot (arrow). Diagrams show interpretation of the ultrasound image and position of imaged tissues. A follow-up observation in case 5 was possible, and Fig. 5, E was taken 3 months after administering BAPC 1500 mg/day. Fig. 5, F was taken 1 month later. Table III summarizes the radiologic appearanceof actinomycosis according to each modality. DlSClJSSlON

Actinomycosis is a chronic granulomatous that causes suppuration and fibrosis. The most commonly isolated organism is an anaerobic, gram-positive, nonacidfast, branched, filamentous bacteria, Actinomyces israelii.’ Actinomyces israelii is a usual inhabitant of the oral cavity. However, under certain

circumstances it penetrates the oral mucous membranes and causes inflammatory changes. It mainly affects soft tissue but sometimes spreads to involve the salivary glands, bone, or even the skin of the face and the neck.lm3,5,6 Swelling and induration of the soft tissue are the most common symptoms.’ This soft tissue swelling usually develops into an abscess that tends to drain through the sinuses.’ When the infection spreads to bone, bone destruction is likely to occur. i, ‘, ’ The disease is usually diagnosed upon microbiologic or histologic examination. Shindo analyzed 140 casesin 49 Japanese facilities. He confirmed the diagnosis microbiologically or histologically in 79

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Fig. 3. A, “Punched-out” pattern on right ramus (arrows). B, CT showsmassto involve pterygomandibular space (arrow). C, Arrow indicates bone erosion. D, Punctate pattern concomitant with pooling of contrast medium.

cases and on the basis of clinical findings in the other 61 cases. However,, when clinical symptoms are not typical, actinomycosis may be misdiagnosed as a tumor.3 Therefore more reliable diagnostic tools are required. CT or other imaging methods were used in just a few reports.5M10Ozaki et a1.8reported a lesion on CT as a well-circumscribed, round mass. Silverman et a1.9 described one: with an ill-defined margin and an enhancing rim surrounding a low density central portion on CT. Lad and Chandy7 and Silverman et a1.9 concluded that CT does not provide the specific diag-

nosis of actinomycosis but helps to define the mass borders and extension more precisely. In our cases, CT helped us to differentiate between inflammatory masses and tumorous masses; in addition, location, extension, and the relationship between the mass and surrounding structures could be clearly defined. On the other hand, bone destruction or bone erosion was readily detectable on CT scans. Cortex destruction without osteolytic bone marrow changes was bordered by a low density soft tissue area, this help us to predict that the destruction was due to extrinsic factors.

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Fig. 3. co&d. E, Hypoechoic masswith irregular margin was detected on US. Note linear pattern of bundles of massetermuscle. Diagram shows interpretation of ultrasound image and position of imaged tissues. Table 111. Radiologic

appearance of actinomycosis as a result of imaging modality Bone

Modality

Soft tissue

Salivary

“Punched-out”pattern radiolucency(If exists) Cortex destruction,no osteoiytic changesof bone marroware seen

NS

US

Cortex destruction (If extensive)

Sialography

NS

Hypoechoic, diffuseareawith hyperechoic spots scattered inside it NS

Panoramic CT

glands

NS

Low density, irregular

soft tissue

densitymass

Low density, irregular density mass

soft tissue

Hypoechoic, ill-defined area with hyperechoic spots scattered inside it If gland is involved: pooling of the contrast medium with filling defect If gland is not involved: pseudofilling defect as a result of the pressure of the mass leading to partial displacement of the gland.

NS. not seen.

Nakamatsu et a1.5and Sazama and Kralove6 used sialography for detecting actinomycosis in the salivary glands. When the gland was involved, Nakamatsu et a1.5 reported a pooling of the contrast medium. Sazama and Kralove6 used the expression “irregular cavities” to describe the same phenomenon. In addition, they reported an irregular filling of the duct with defects of the contrast medium. In our cases, similar findings were detected. However, in one case when the gland was not involved but was pressed

by the mass, a pseudofilling defect was observed. This was confirmed in the second case, in which the CT-sialography showed the ducts to be completely filled. Sazama and Kralove6 emphasized the role of sialography for diagnostic and therapeutic purposes even though it provides no characteristic signs of actinomycosis. Although we agree with Sazama and Kralove6 on the important diagnostic role of sialography, we would like to emphasize the role of CT-sialography. Using both modalities separately and in

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Fig. 4. A, MRI shows high signal intensity area around condylar process (arrow). Note same signal of masseter muscle. B, Arrow indicates cortex destruction. C, CT shows swelling of masseter and internal pterygoid muscles. D, CT shows diffuse low density area on internal surface of masseter (arrow). E, Diffuse hypoechoic area between masseter muscle and ramus. Diagram shows interpretation of ultrasound image and position of imaged tissues.

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Fig. 5. A, “‘Punched-out” pattern on right ramus (arrows). Note sclerotic bone. , Arrows indicate cortex destruction. 6, CT shows mass in perimandibular area (arrow). Note enlargement of masseter muscle.

combination would definitely lead to a better understanding of the condition of the disease, such as whether the salivary gland is involved or not. Hardoff et aLro used scintigraphy, which helped him to identify the inflammatory nature of the disease. Most of the imaging modalities do not provide specific information about actinomycosis but help to identify its inflammatory nature and differentiate it from neoplasms. Siegert” conducted an investigation of ultrasonography of inflammatory tissue swellings of the head and neck. He could define two types of abscesses; type one has no internal echoes (echofree), and type two is echopoor (it has only a few internal echoes). Because of the high sensitivity and specificity of US, he strongly recommended it as an inexpensive, noninvasive routine diagnostic tool for imaging oral and maxillofacial disease.

The inflammatory nature of cases in our report could be predicted because most of the cases were hypoechoic (echofree as in Siegert”). Furthermore, the linear pattern of the bundles of the masseter muscle indicates inflammatory change detectable on US. ;“Iowever, though actinomycosis is an inflammatory disease, it’s echo appearance should be differentiated from that of ordinary abscesses. Siegert’ t stated that abscesses appear as slightly delineated areas that are either echofree, or echopoor. US of actinomycosis in the present report revealed a mass with an ill-defined margin that was hypoechoic with relatively large hyperechoic spots inside it. These points may help to differentiate actinomycosis from ordinary abscesses, and therefore the diagnosis might be possible to predict. Neither CT nor US alone can provide a definite diagnosis for actinomycosis. However, using US would help predict the inflammatory nature of the disease.

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Fig. 5. eont’d. D, Hypoechoic, irregular structure detected upon US. Arrows indicate cortex destruction. of BAPC. “Punched-out” pattern is less visible. Bone sclerosis is also improving. F, Lateral-oblique view of patient taken 1 month later. Bone sclerosis is improving. Diagram for ultrasonography. E, Panoramic view taken 3 months after administration

On the other hand, CT would help to detect bone destruction and extension of the diseaseas well. Besides it is necessaryto usesialography when salivary glands massesare suspected.As summarized in Table III and stated in the discussion above, a diagnosis of actinomycosis could be developedby combining the findings of imaging modalities.

2. Kondo T, Ohta Y, Matsumoto Y, Matsuura M, Seto K, Shindo J. Central actinomycosis of the mandible: report of a case.Jpn J Oral Maxillofac Surg 1983;29:132-8. 3. Bennhoff D. Actinomycosis: diagnostic and therapeutic considerations and a review of 32 cases. Laryngoscope 1984; 94:1198-217. 4. Shindo J. The situation of oral actinomycosis: analysis of 140 casesin 45 facilities. Jpn J Oral Maxillofac Surg 1983;29:1525. 5. Nakamatsu K, Shinohara M, Takenoshita Y, Higuchi K, Kimura S, Oka M. Two casesof actinomycosis of the submandibular gland region. Jpn J Oral Maxillofac Surg 1986;32:68-

REFERENCES

14. 6. Sazama L, Kralove H. Actinomycosis of the parotid gland: report of five cases. ORAL SURG ORAL MED ORAL PATHOL 1965;19:197-204.

1. Shafer W, Hine ;M, Levy B, eds.A textbook of oral pathology. Philadelphia: WB Saunders Company, 1983;346-9.

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7. Lad S, Chandy M. Craniofacial actinomycosis. Br J Neurosurg 1991;5:361-70. 8. Ozaki W, Abubaker 0, Sotereanos G, Patterson G. Cervicofacial actinomycosis following sagittal split ramus osteotomy: a case report. J Oral Maxillofac Surg 1992;50:649-52. 9. Silverman P, Farmer J, Korobkin M, Wolfe J. CT diagnosis of actinomycosis of the neck. J Comput Assist Tomogr 1984;8:793-4. 10. Hardoff R, Gips S, Meyer Y, Kelner U. Cervicofacial actinomycosis evaluated by multiple imaging studies. Clin Nucl Med 1989;14:216-7.

ORAL SURGERY ORAL MEDICliVE ORAL PATHOLOGY December 1993 11. Siegert R. Ultrasonography of inflammatory soft tissue swellings of the head and neck. J Oral Maxillofac Surg 1987; 45:842-6. Reprint requests: Banna Sa’do, DDS, PhD Department of Oral and Maxillofacial Radiology Faculty of Dentistry, Kyushu University 3-l-l Maidashi, Higashi-ku Fukuoka 812Japan

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