A rare case report of Ectopic Cervical Thymoma

A rare case report of Ectopic Cervical Thymoma ISSN: 2394-0026 (P)Case Report ISSN: 2394-0034 (O)A rare case report of Ectopic Cervical ThymomaBharathi M.1, Giri Punja M.2*, Shilpa K.3, Geetanjali S.21Professor and Head, 2PG Student, 3Associate ProfessorDepartment of Pathology, Mysore Medical College and Research Institute, Mysore, Karnataka, India*Corresponding author email: [email protected] to cite this article: Bharathi M., Giri Punja M., Shilpa K., Geetanjali S. A rare case report ofEctopic Cervical Thymoma. IAIM, 2015; 2(3): 175-178.Available online at www.iaimjournal.comReceived on: 10-02-2015 Accepted on: 26-02-2015AbstractThe thymus, a lymphoepithelial organ, during the early fetal life originates from the superior neckand descends to the mediastinum. Embryological maldescent may lead to ectopic rests of thymictissue along the pathway of its descent, neck being the most common site of ectopic thymic rests.Ectopic cervical thymoma is an extremely rare entity, showing a striking female preponderancewhereas a mediastinal thymoma has a slight female preponderance. We characterized a case ofectopic cervical thymoma using conventional light microscopy and immunohistochemistry in a 40years old male patient who presented with a neck swelling simulating a thyroid neoplasm clinically.Key wordsThymoma, Ectopic, Mediastinum.Introduction ectopic thymic tissue, cysts and neoplasms of the cervical thymus. Rarely, an ectopic thymusThymus originates in the embryo from the may lead to the development of malignantventral ring of 3rd and 4th pharyngeal pouches thymoma [3].and ectoderm endoderm of the cervical sinus, asepithelial outgrowths on each side [1, 2]. Being Case reportlocated in the upper anterior mediastinum andlower part of the neck, the thymus is active A 40 years old male patient presented to theduring childhood and involutes after puberty surgical outpatient department with the historybeing replaced by adipose tissue gradually of a palpable midline swelling in the neck, justthereafter, although it never disappears above the supra-sternal notch. There was nocompletely [3]. Remnants of the thymic tissue associated dysphagia or pain. On physicalmay be sequestered in the neck during its examination, the mass was 3 cm in diameter,migration into the mediastinum, resulting in non-tender and was not moving withInternational Archives of Integrated Medicine, Vol. 2, Issue 3, March, 2015. Page 175Copy right © 2015, IAIM, All Rights Reserved.

A rare case report of Ectopic Cervical Thymoma ISSN: 2394-0026 (P) ISSN: 2394-0034 (O)deglutition. He was clinically diagnosed to have A final diagnosis of mixed thymoma (type AB)ectopic thyroid in supra-sternal region. The was arrived at and confirmed with positive CK14patient was euthyroid clinically and and CD5 immune markers. (Photo – 3, Photo –biochemically. 4) Photo - 2: Microphotograph showing oval toA fine needle aspiration exhibited dispersed spindle epithelial cells with bland vesicularpopulation of mature lymphocytes, plasma cells nuclei admixed with lymphocytes. (400X)with few histiocytes and was opined as non-specific lymphadenitis.Patient underwent a transverse cervicotomy, Photo - 3: Microphotograph showing positivefollowed by excision, and histopathological immunostain for cytokeratin 14. (400X)examination of the excised mass wasperformed. Gross examination showed a fairlywell circumscribed mass measuring 3.2 cm in itsgreatest dimension. On sectioning of the tumormass, homogenous gray white areas wereidentified. Histology revealed an encapsulatedtumour mass with fibrous septae extending anddividing the tumor into multiple lobules. Thelobules were composed of dual population ofcells, spindle cells with oval to spindle, blandvesicular nuclei admixed with sheets of smallmature lymphocytes. (Photo – 1, Photo – 2)Rosettes, perivascular spaces and glandularstructures were noted along with typical hasall’scorpuscles. It showed no evidence of cellularatypia or increased mitotic count.Photo - 1: Microphotograph showing varyingproportions of epithelial cells and lymphocytesin thymoma. (100X) Photo - 4: Microphotograph showing positive immunostain for CD5. (400X)International Archives of Integrated Medicine, Vol. 2, Issue 3, March, 2015. Page 176Copy right © 2015, IAIM, All Rights Reserved.

A rare case report of Ectopic Cervical Thymoma ISSN: 2394-0026 (P) ISSN: 2394-0034 (O)Discussion with myasthenia gravis in humans, there is noThymus was originally believed to be the seat of well documented causative factor for thethe soul and near recently to be the “clock for development of thymoma. Thymoma is alsoimmunologic aging” [4]. known to be associated with pure red cell aplasia and Good’s syndrome.Maldescent of the thymus during embryonic life Thymomas being slow growing tumours haveexplains the ectopic thymic rests such as in the excellent prognosis when diagnosed in theirneck, thyroid, lung, pleura, skull base, root of early stages and treated. For thymoma, tumourthe bronchus, and in the mediastinum [5]. staging is the single most important prognosticMajority of the ectopic thymic nodules are factor. Neoplastic thymic epithelial cells lack CD5located in the neck with close proximity to the expression and show cytokeratin positivitythyroid gland, frequently resulting in a mistaken whereas the non-neoplastic lymphoid cells showclinical impression of a primary thyroid disorder. CD5 positivity. As in our case, most ectopicEndodermally derived epithelial cells and bone- cervical thymomas diagnosed as thyroidmarrow derived lymphocytes are the two major tumours were removed simply by a neckcell types in thymus. Ectopic thymus can be incision; exact diagnosis was made only after theunilateral or bilateral. About 20% of humans post-operative histopathological examination.harbour aberrant nodules of thymic tissue;however ectopic cervical thymoma is a rare Our patient underwent a repeat surgery foroccurrence [3, 6]. extended thymectomy and is doing well with 2 years follow up.Thymoma is a thymic epithelial neoplasm,accompanied by reactive lymphoid cells in Conclusionvarying numbers, and exhibit organotypic In conclusion, clinicians and pathologists mustfeatures including medullary differentiation, be aware of this rare entity as timely diagnosislobulation, presence of immature T-lymphocytes and proper management of the patient offersand perivascular spaces. Thymomas frequently good clinical outcome.occur in fifth and sixth decades, with a mean ageof 49.5years [7]. Although the mediastinal Referencesthymoma shows an equal sex incidence or a 1. Thakur A, Sebag F, Micco CD, Slotema E,slight female preponderance, an unexplained Henry FJ. Ectopic cervical thymomaand striking preponderance for females is seen mimicking as papillary thyroidin ectopic cervical thymoma. The incidence of carcinoma: A diagnostic dilemma. Indianectopic thymoma is about 4% [1]. The most J Pathol Microbiol, 2010; 53: 305-7.common presenting symptom of an ectopic 2. Ramdas A, Jacob SE, Varghese RG,cervical thymoma is an enlarging neck mass and Dasiah S, Rai R. Ectopic cervicalis frequently misdiagnosed on fine needle thymoma - the great mimic: A caseaspiration cytology. The diagnosis is difficult to report. Indian J Pathol Microbiol, 2007;make and has a major diagnostic pitfall [8]. 50(3): 553-5. 3. Jung JI, Kim HH, Park SH, Lee YS.Tumour cells of the thymus grow slowly, look Malignant Ectopic Thymoma in thesimilar to the normal thymus cells and rarelyspread to the neighbouring structures. Althoughthymoma is known to be intricately associatedInternational Archives of Integrated Medicine, Vol. 2, Issue 3, March, 2015. Page 177Copy right © 2015, IAIM, All Rights Reserved.

A rare case report of Ectopic Cervical Thymoma ISSN: 2394-0026 (P) ISSN: 2394-0034 (O)Neck: A Case Report. Am J Neuroradiol , Thymoma - A Case Report. The Korean1999; 20: 1747–1749. Journal of Pathology, 2010; 44: 444-7.4. Kay MMB. The thymus: Clock for 7. Sperling B, Marschall J, Kennedy R, et al.immunologic aging? J Invest Dermatol, Thymoma: A review of the clinical and1979; 73: 29. pathological findings in 65 cases. Can J5. Yan B, Lim D, Petersson F. Ectopic Surg., 2003; 46: 37-42.Cervical Thymoma: A Report of Two 8. Wu TH, Jin JS, Huang TW, Chang H, LeeCases of a Rare Entity Frequently SC. Ectopic cervical thymoma in aMisdiagnosed on Fine Needle Aspiration patient with Myasthenia gravis. JournalCytology and Frozen section. Head Neck of Cardiothoracic Surgery, 2011, 6: 89.Pathol., 2010; 4(2): 152–156.6. Jin XJ, Song JY, Choi1 SJ, Kim L, Park IS,Han JY. Aspiration Cytology of CervicalSource of support: Nil Conflict of interest: None declared.International Archives of Integrated Medicine, Vol. 2, Issue 3, March, 2015. Page 178Copy right © 2015, IAIM, All Rights Reserved.