Recurrent submandibular pleomorphic adenoma with metastasis: Carcinoma ex pleomorphic adenoma :Ajil Antony, R Santhoshkumar, Kerala Surgical Journal

CASE REPORT
Year : 2022 | Volume : 28 | Issue : 1 | Page : 93--97

Recurrent submandibular pleomorphic adenoma with metastasis: Carcinoma ex pleomorphic adenoma

Ajil Antony¹, R Santhoshkumar²,
¹ Department of General Surgery, Medical College Hospital, Kozhikode, Kerala, India
² Department of General Surgery, Government Medical College, Kozhikode, Kerala, India

Correspondence Address:
Dr. Ajil Antony
Department of General Surgery, Medical College Hospital, Kozhikode - 673 001, Kerala
India

Abstract

Carcinoma ex pleomorphic adenoma (CXPA) is a carcinoma arising from a primary or recurrent benign PA. The entity is difficult to diagnose preoperatively. PA is a common neoplasm that arises from the major salivary glands and infrequently undergoes a malignant transformation. PA can metastasise without histological malignant transformation. Malignant changes in PA are associated with a long duration, tumour recurrence, radiation therapy, advancing age and tumour size. Since the incidence of malignancy is correlated with the duration of PA, the risk of developing malignancy is only about 1.5% for a duration of <5 years, but increases to 9.5% for a duration of >15 years. We describe a case of CXPA of submandibular salivary gland in a 70-year-old female who had a history of right submandibular sialoadenectomy in 2017 and then redo excisions at the same site in 2018 and 2021.

How to cite this article:
Antony A, Santhoshkumar R. Recurrent submandibular pleomorphic adenoma with metastasis: Carcinoma ex pleomorphic adenoma.Kerala Surg J 2022;28:93-97

How to cite this URL:
Antony A, Santhoshkumar R. Recurrent submandibular pleomorphic adenoma with metastasis: Carcinoma ex pleomorphic adenoma. Kerala Surg J [serial online] 2022 [cited 2023 Mar 24 ];28:93-97
Available from: http://www.keralasurgj.com/text.asp?2022/28/1/93/350904

Full Text

Introduction

Tumours of submandibular gland are uncommon, slow-growing and painless. About 60%–70% of submandibular gland tumours are benign.[1] Pleomorphic adenoma (PA) is the most common benign tumour.[2] It can occasionally undergo malignant transformation to carcinoma ex PA (CXPA). More rarely PA can metastasise without a histological malignant transformation, especially when incomplete excision is performed. Three most common sites are bone (36.6%), lung (33.8%) and cervical lymph nodes (20.1%). Clinical features of high grade malignant salivary tumours: facial nerve weakness, rapid enlargement of the swelling, induration and ulceration of the overlying skin and cervical node enlargement.[3]

Initial investigation of choice is ultrasonography-guided fine-needle aspiration cytology (FNAC) or True-Cut biopsy. Computed tomography (CT)/magnetic resonance imaging is beneficial to know the relationship of tumour to other anatomical structures, which is helpful in planning surgery. Management for benign tumours is dissection outside the submandibular capsule. Malignant tumours are treated based on the stage and clinical grade of the lesion. Larger and aggressive lesions require radical surgery. Wide clearance of the submandibular triangle with some form of neck dissection is normally the treatment of choice. Adjuvant radiotherapy may be needed for close margins and high-grade cancers. Prognostic cuff point for salivary gland cancers is 4 cm and tumours larger than this require adjuvant radiotherapy as well. We present here a rare case of CXPA in the submandibular salivary gland.

Case Report

A 70-year-old female presented with swelling over the right side of the face and neck. She had a history of right submandibular sialoadenectomy in November 2017 and re-excision in September 2018. There was no associated pain or skin changes. There was no loss of weight. On examination, there was an irregular swelling of 16 cm × 10 cm × 6 cm extending from the zygoma to the level of thyroid cartilage vertically and horizontally from behind the body of the mandible to 1 cm to the left of the midline mainly in the submandibular region extending into the upper part of the neck on the right side [Figure 1] and [Figure 2]. The surface was bosselated and edges well defined. It was variable inconsistency with firm and soft areas. There was no fixity to skin and underlying muscle. Skin over the swelling was normal. The swelling was palpable on the floor of the mouth. Tonsils were pushed to the opposite side. Protrusion of tongue was restricted. The right temporomandibular joint showed normal mobility. No lymph node was palpable in the cervical region. FNAC was suggestive of PA, and core needle biopsy was consistent with PA. She was advised excision biopsy of the swelling to rule out CXPA. Contrast-enhanced CT (CECT) of the head, neck and thorax showed a large heterogeneous lesion of the right submandibular region (submandibular gland not separately visualised), extending laterally through the undersurface of the angle of the mandible to the outer aspect (cortex of mandible appears irregular but no definite bony destruction). It was medially extending into the sublingual space with lost fat planes with intrinsic and extrinsic muscles of the tongue. Posteromedially, it is noted protruding into the oropharynx, showing lost fat planes with the hyoid bone, thyroid lamina and strap muscles over it. Posteriorly, it is pushing the right sternocleidomastoid muscle and structures of the carotid canal with lost fat plains with sternocleidomastoid and right parotid gland [Figure 3] and [Figure 4]. Multiple subcentimetric cervical lymph nodes were noted. Chest X-ray showed bilateral lower lung zone opacities, suspicious of metastasis [Figure 5]. CECT of lungs showed multiple enhancing lesions involving both lung parenchyma, largest measuring 5.4 cm × 4.8 cm in lingular segment of the upper lobe, suggestive of metastasis [Figure 6] and [Figure 7]. Provisional diagnosis was CXPA with metastasis of the submandibular salivary gland. The plan was debulking surgery [Figure 8], [Figure 9], [Figure 10].{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}{Figure 7}{Figure 8}{Figure 9}{Figure 10}

During surgery, an 18 cm × 8 cm × 6 cm swelling was seen involving the right submandibular region with infiltration to surrounding structures extending superiorly to the parotid gland, laterally to sternocleidomastoid and inferiorly to the neck infiltrating strap muscles. Submandibular gland was not separately identified. Intramural extension was not explored. Histopathology showed myoepithelial predominant PA, showing infiltrative borders and areas of necrosis. There was no increase in mitosis or lymphovascular emboli [Figure 11] and [Figure 12].{Figure 11}{Figure 12}

Post-operative positron emission tomography- fluorodeoxyglucose (FDG) scan showed wedge-shaped surgical defect in the right submandibular region-status post-surgery. There was FDG non-avid area of hypodense collection in submandibular fossa – likely post-operative seroma. FDG-avid soft-tissue thickening was noted in surgical margins involving the submandibular and floor of mouth region – likely residual disease. FDG-avid right 1A and right 1B cervical lymph nodes, likely locoregional metastatic disease and FDG-avid multiple pleural and parenchymal nodules in lung fields and subcarinal and pericardial lymph nodes, likely metastatic disease [Figure 13] were noted. CT-guided biopsy of lung lesion showed the linear core of fibrocartilaginous tissue showing cells scattered and clusters with enlarged with atypical round nucleus, mild-to-moderate eosinophilic cytoplasm and nucleoli in conspicuous myxoid areas. Few clear cells with peripheral nuclei were also seen. This was consistent with PA with doubtful metastases [Figure 14] and [Figure 15].{Figure 13}{Figure 14}{Figure 15}

Discussion

CXPA is a carcinoma arising from a primary or recurrent benign PA.[1],[2] PA is the most common benign neoplasm of the salivary glands. It is usually found in the parotid gland, but it can also arise in the submandibular, sublingual and minor salivary glands.[3],[4] It is well known that PA occasionally undergoes malignant transformation to CXPA and can metastasise. More rarely PA can metastasise without a histological malignant transformation, especially when incomplete excision was performed.[5],[6] The neoplasm generally affects the major salivary glands, especially the parotid and submandibular glands[7],[8] There are three subtypes malignant PA: CXPA, carcinosarcoma and metastasising PA. The most common subtype is CXPA which develops in primary or recurrent PA.[9] The macroscopic features that suggest malignant transformation include poorly defined and/or infiltrative tumour margins, the presence of foci of haemorrhage and necrosis.[10] The main histopathological finding in CXPA is the coexistence of the benign characteristics of PA and malignant changes in the epithelial components of the tumour.[11],[12] The optimal treatment is wide local excision with or without post-operative radiotherapy.[13]

Conclusions

CXPA is a malignancy of clinical and pathological relevance. There is a wide range of biological behaviour of this tumour. Radical surgery is the treatment, followed by radiotherapy in view of its cosmetic disfigurement and peculiarity of recurrence.

Declaration of patient consent

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

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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