|Year : 2017 | Volume
| Issue : 6 | Page : 215-219
Toxoplasmosis lymphadenitis of parotid gland concurrent with papillary thyroid carcinoma: A dilemma in differential diagnosis
Yu-Chen Hsu1, Chien-Chin Chen2, Chih-Hsuan Changchien3
1 Department of General Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
2 Department of Pathology, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
3 Department of Plastic and Reconstructive Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
|Date of Submission||13-Feb-2017|
|Date of Decision||13-Apr-2017|
|Date of Acceptance||22-May-2017|
|Date of Web Publication||08-Dec-2017|
Department of Plastic and Reconstructive Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, No. 539, Zhongxiao Road, East District, Chiayi City 60002
Source of Support: None, Conflict of Interest: None
We report a case of toxoplasmosis lymphadenitis simulating a parotid mass concurrent with a papillary thyroid carcinoma. A 55-year-old male presented symptomless masses in the left lower neck and right preauricular region for 2 months. Physical examination revealed a 2 cm × 2-cm firm mass in the right parotid region and a 3-cm diameter soft mass in the left lobe of thyroid gland. Computed tomography confirmed a lobulated nodule, embedded in the right parotid gland, and; a left thyroid nodule, which resembled a papillary thyroid carcinoma. Fine-needle aspiration (FNA) of the left thyroid lobe suggested a papillary thyroid carcinoma. A radical thyroidectomy, central neck lymph node dissection, and right superficial parotidectomy were performed. Histopathological examination of the surgical specimen supported the diagnosis of a papillary carcinoma of the left thyroid lobe and toxoplasmosis lymphadenitis in the right parotid gland. Specific serum immunoglobulin tests suggested a current infection with Toxoplasma gondii. The patient was administered pyrimethamine and sulfadiazine for 4 weeks and underwent I-131 ablation for the functional thyroid remnants in the anterior neck. At a 16-month follow-up, the patient was clinically fit and recurrence free. This case highlights the importance of remaining clinically vigilant to differentiate an unusual metastatic carcinoma from inflammation of the parotid gland. A consideration of toxoplasmosis lymphadenitis by thorough history taking, appropriate serologic tests, and selective use of FNA may provide combined preoperative information for differential diagnosis of a parotid mass and help avoid an unnecessary surgical procedure.
Keywords: Lymph node, parotid gland, thyroid carcinoma, toxoplasmosis
|How to cite this article:|
Hsu YC, Chen CC, Changchien CH. Toxoplasmosis lymphadenitis of parotid gland concurrent with papillary thyroid carcinoma: A dilemma in differential diagnosis. Formos J Surg 2017;50:215-9
|How to cite this URL:|
Hsu YC, Chen CC, Changchien CH. Toxoplasmosis lymphadenitis of parotid gland concurrent with papillary thyroid carcinoma: A dilemma in differential diagnosis. Formos J Surg [serial online] 2017 [cited 2020 Sep 26];50:215-9. Available from: http://www.e-fjs.org/text.asp?2017/50/6/215/220347
| Introduction|| |
The wide variety and heterogeneous nature of solid parotid masses lead to difficulties, at least to some extent, in differential diagnosis by clinicians and radiologists. Involvement of the lymph nodes near the parotid gland in metastatic carcinoma, lymphoma, or unusual inflammatory disorders is often misdiagnosed as a primary parotid tumor. In this article, we report a case of toxoplasmosis lymphadenitis that simulated a parotid mass concurrent with a papillary thyroid carcinoma. An English literature review based on the PubMed database dating back to 1980 revealed extremely rare well-documented case reports on toxoplasmosis lymphadenitis of the parotid gland. To the best of our knowledge, this is the first report in the literature of a case concurrent with a papillary carcinoma of thyroid gland.
| Case Report|| |
A 55-year-old male was admitted to our surgical ward due to symptomless masses in the left lower neck and right preauricular region; the masses had been persistent for 2 months. Clinical examination revealed an elastic, firm, and fixed mass, approximately 2 cm in diameter, within the right parotid gland and a round, soft mass, 3 cm in diameter, within the left lobe of the thyroid gland. No other palpable cervical lymph node was detected. Facial nerve function was intact. Routine laboratory investigations were unremarkable. Head and neck computed tomography (CT) [Figure 1] confirmed a lobulated nodule embedded in the right parotid gland with postcontrast homogeneous enhancement; the nodule resembled a Warthin's tumor or intraglandular node [Figure 2]. The CT also revealed a left thyroid nodule with rim calcification, heterogeneous enhancement, and loss of strap muscular fat plane; this nodule resembled a papillary thyroid carcinoma or goiter. Fine-needle aspiration (FNA) of the left thyroid lobe revealed the presence of atypical cells with enlarged nuclei, pallor chromatin, nuclear grooves, and nuclear membrane irregularity or nuclear molding, suggesting a papillary thyroid carcinoma.
|Figure 1: Head and neck computed tomography confirmed a right parotid gland mass that presented concurrently with a left thyroid gland mass|
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|Figure 2: Face computed tomography. A lobulated nodule (1.6 cm in diameter) at the right preauricular region posterior to the right mandible, embedded in the superficial lobe of the right parotid gland with postcontrast homogeneous enhancement and no calcification|
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The patient underwent radical thyroidectomy, central neck lymph node dissection, and right superficial parotidectomy. Histopathological analysis of an intraoperatively obtained frozen section confirmed a papillary carcinoma of the left thyroid lobe and a reactive hyperplasic lymph node in the right parotid gland. Subsequent examination of the lymph node showed numerous foci of small noncaseating granulomas comprising epithelioid histiocytes within or around the hyperplastic germinal centers. There were also multiple areas of monocytoid B-cell hyperplasia [Figure 3] and [Figure 4]. The morphology was compatible with toxoplasmosis lymphadenitis; thus, further serological testing of the patient was performed. The following toxoplasma serum titers were measured using a chemiluminescent microparticle immunoassay: toxoplasma immunoglobulin G (IgG), 106.0 IU/mL (normal, <1.6 IU/mL) and immunoglobulin M (IgM), 0.980 index (normal, <0.5 index). Enzyme-linked immunosorbent assay exhibited low-level avidity of Toxoplasma-specific IgG. However, the findings of polymerase chain reaction (PCR) analysis were negative. The results of these tests collectively suggested a current infection with Toxoplasma gondii. Retrospective questioning of the patient confirmed that he had close contact with a domestic cat.
|Figure 3: Histological examination of the right parotid lymph node revealed the characteristic triad of toxoplasmosis lymphadenitis: Reactive follicular hyperplasia (see red area), monocytoid B-cell reaction (see blue area), and clusters of epithelioid histiocytes (see yellow arrows) (hematoxylin and eosin, ×100)|
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|Figure 4: Higher magnification demonstrated epithelioid histiocytic aggregates forming microgranulomas and the absence of giant cells (see yellow arrows) (hematoxylin and eosin, ×200)|
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The patient was administered a combination of pyrimethamine and sulfadiazine for 4 weeks and underwent I-131 ablation for the functional remnants of the thyroid in the anterior neck. At a 16-month follow-up, the serological titers had decreased, and the patient was clinically fit without any manifestation of the palpable recurrent disease.
| Discussion|| |
Toxoplasmosis is a zoonotic infectious disease that occurs worldwide and is caused by T. gondii, an intracellular cyst-forming protozoan parasite. Cats are the most frequently recognized definitive hosts. The major route of transmission to humans is by ingestion of either undercooked meat containing cysts or food contaminated with shedding cyst. In rare cases, the transmission may transplacentally occur or it may occur after blood transfusions or organ transplantation, leading to severe adverse effects. In immunocompetent individuals, symptoms of acquired toxoplasmosis are often self-limited, resembling a common cold with cervical or occipital lymphadenopathy. Involvement of the intraglandular lymph nodes of the parotid gland in toxoplasmosis is not uncommon, but easily overlooked, and most healthy individuals recover from toxoplasmosis with no treatment unless symptoms are persistent or severe. However, immunocompromised patients may experience serious extranodal diseases such as myocarditis, chorioretinitis, pneumonitis, or infections of central nervous system. Pyrimethamine and sulfonamides medications are both active against the tachyzoite form of toxoplasmosis and can be prescribed to immunocompromised patients with active infections.
Preoperative confirmatory diagnosis of parotid toxoplasmosis is not easy. A high degree of suspicion and careful history including the exposure to cats or the consumption of undercooked meat may provide some hints of preoperative impression. Routine serologic investigations for a major salivary mass is still controversial. The most consistent evaluation of toxoplasmosis is by serologic testing for antibodies (IgM and IgG), IgG avidity assay and a histopathologic study of the mass. Detection of T. gondii DNA by PCR has also proven to be an alternative and supportive method for the diagnosis of toxoplasmosis. Radiologic examinations are not useful. FNA is widely used for differential diagnosis of salivary gland lesions and metastatic malignancy. However, an accurate histopathological diagnosis of toxoplasmosis lymphadenitis requires a well-preserved architecture of the entire lymph node. It is difficult to match the fragile and limited tissue obtained by FNA to the characteristic histopathological triad as the criterion for the histopathological diagnosis of toxoplasmosis lymphadenitis [Figure 3].
An additional consideration in this reported case is that reliance on reports in the literature for the parotid gland and surrounding lymph nodes may potentially involve metastatic thyroid carcinoma. Theoretically, right parotid gland seems not to be the metastatic lesion of left thyroid cancer without other surrounding suspicious metastatic lymph nodes of the right lateral neck. However, an isolated submandibular metastasis from a contralateral thyroid papillary microcarcinoma has been reported. Therefore, for a parotid mass where the clinical diagnosis is compromised, selective use of FNA may provide additional clues for differential diagnosis of the metastatic diseases.
An English literature review based on the PubMed database dating back to 1980 revealed 11 well-documented cases [Table 1], the average duration of a symptomless parotid mass was approximately 2 months, the average patient age was 36.7 years, and the male to female ratio was 1:1. Five patients received antimicrobial therapy before surgery but were unresponsive, and five patients underwent FNA, but the analysis was nondiagnostic. Toxoplasmosis lymphadenitis is an often unsuspected cause and is rarely considered in differential diagnosis of a parotid mass. In most instances, serologic tests for the diagnosis of toxoplasmosis are not routinely performed to assess a parotid gland mass. Our review of the literature revealed that only one patient was diagnosed preoperatively by serologic testing. However, preoperative medical treatment failed, and the patient subsequently underwent parotidectomy. All the reviewed cases notably underwent superficial parotidectomy or mass excision. Therefore, surgical management still plays a role in the diagnosis and treatment of the toxoplasmosis lymphadenitis of the parotid gland. IgG titer results were not comparable among the reviewed cases because of the use of various serologic assays. Retrospective questioning for the exposure to cats or the consumption of undercooked meat was performed for six patients. After confirmation of toxoplasma infections in 11 patients, three were postoperatively prescribed systemic antimicrobials, whereas the other eight were not. Two patients who were not prescribed postoperative antimicrobials notably experienced postoperative recurrence, although the symptoms resolved after antimicrobial treatment. The other nine patients were clinically fit without recurrence during the follow-up period. However, it remains unclear as to whether postoperative antimicrobial treatment is required for toxoplasmosis lymphadenitis of the parotid gland because of the small number of case reports.
|Table 1: Clinical features of toxoplasmosis lymphadenitis of the parotid gland|
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Presentation of toxoplasmosis lymphadenitis as a solid parotid mass concurrent with a thyroid carcinoma is rare. This case highlights the importance of remaining clinically vigilant to differentiate an unusual metastatic carcinoma from inflammation of the parotid gland. A consideration of toxoplasmosis lymphadenitis by thorough history taking and careful clinical examination with appropriate serologic testing and selective use of FNA may provide combined preoperative information for the differential diagnosis of parotid mass and help avoid an unnecessary surgical procedure.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his 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.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]