A Mullerian cyst resected from the posterior mediastinum.
Traditionally, cysts found within the posterior mediastinum have been universally diagnosed as masses of neurogenic or bronchogenic origin. However, since Hattori first noted the Mullerian cyst within the mediastinum, increasing case reports have mirrored his findings. (1)
Our patient is a 49-year-old black woman with a known history of a posterior mediastinal mass discovered after developing a non-productive cough. Her past medical history includes gastroesophageal reflux disease (GERD) and obesity. On exam, our patient had clear breath sounds bilaterally with no abnormal vital signs and no history of fever. A radiograph (Figure 1) revealed a left-sided posterior mediastinal mass. Computer tomography (CT) scan with IV contrast (Figure 2) showed a 3.4 x 3.6 x 3.0 cm mass posterior to the aortic arch in the left paravertebral location.
Due to worsening cough and concern for malignancy, the patient and our surgical team planned for surgical removal of the mass. A left posterolateral thoracotomy was performed. The cyst was adhered to the aortic arch in the left paravertebral location and was entered during surgical removal. The cyst was pink and the cystic fluid had a serous, pink-tinged appearance. The fluid and cyst were sent for permanent pathology. There was no malignancy or atypia and the cyst was lined by Mullerian type epithelium (WT-1, ER, PR, PAX-8 and CK-7 immunoreactive) (Figure 3). The patient had an uneventful postoperative course and was discharged home. Thus far she has had no evidence of recurrence.
Our patient described above follows the typical course of the Mullerian cyst when compared to the literature: A posterior mediastinal mass is discovered either incidentally or during workup of respiratory or cardiac symptoms, the mass is resected, and barring any surgical complications the patient has a benign follow-up.
Hattori first described the Mullerian cyst in 2005. In the decade since this publication, multiple case reports have examined similar lesions. In 2007, Businger et al. published a similar case treated by Video-Assisted Thoracoscopic Surgery who was on hormone replacement therapy. (2) In 2010, Batt published a case report of the first Mullerian cyst within the USA, which also had a typical presentation when compared to the literature. (3) Kobayashi in 2012, Simmons in 2013 (who reported two separate cases), and Chon in 2014 reported mediastinal cysts that had expectant follow-ups. (4,6) Skancke published a novel report demonstrating bilateral Mullerian mediastinal cysts. (7) While it did demonstrate the first case in terms of multiple such lesions, it did not show any difference in clinical significance.
Two groups have retrospectively evaluated their own patient populations. The first was Hattori, who was the first to report the novel pathology of the Mullerian cyst. In 2005, his pathology files from 1996-2004 were examined, and of 19 mediastinal cysts, three (16%) of the cysts demonstrated Mullerian degeneration. (8) De Montpreville published a study in 2006 examining 163 mediastinal nonneoplastic cysts discovering nine (5.5%) cysts with Mullerian differentiation. (9) No follow-up studies have been published, but based on the lack of literature demonstrating recurrence or malignant transformation after removal, it has been accepted that removal is the standard of care. Surgical removal effectively rules out the presence of malignancy with no long-term ill effects.
Based on a review of the literature, it is likely that the Mullerian cyst has historically been underdiagnosed until recently. Although it is a distinctly different entity on a pathological level, the management of the Mullerian cyst is similar to the more commonly encountered bronchogenic and neurogenic masses in that resection is recommended due to potential for late malignant transformation. Long-term follow-up is to be determined due to the relatively recent discovery of these masses, but since their recognition in 2005 there are no reports of malignant behavior. Nonetheless, it is a diagnosis this should be considered and discussed when planning for surgical resection of mediastinal masses.
(1.) Hattori H. Ciliated cyst of probable mullerian origin arising in the posterior mediastinum. Virchows Arch 2005;446:82-4.
(2.) Businger AP, Frick H, Sailer M, et al. A ciliated cyst in the posterior mediastinum compatible with a paravertebral Mullerian cyst. Eur J Cardiothorac Surg 2008; 33: 133-6. Epub 2007 Oct 31.
(3.) Batt RE, Mhawech-Fauceglia P, Odunsi K, et al. Pathogenesis of mediastinal paravertebral mullerian cysts of Hattori: developmental endosalpingiosis-mullerianosis. Int J Gynecol Pathol 2010; 29: 546-51.
(4.) Kobayashi S, Inoue T, Karube Y, et al. A case of Mullerian cyst arising in posterior mediastinum. Ann Thorac Cardiovasc Surg. 2012;18:39-41.
(5.) Simmons M, Duckworth LV, Scherer K, et al. Mullerian cysts of the posterior mediastinum: report of two cases and review of the literature. J Thorac Dis 2013;5:E8-10.
(6.) Chon SH, Im UJ, Song DS. Paravertebral mediastinal Mullerian cyst resected by video assisted thoracoscopic surgery. J Thorac Dis. 2015;7(3):E47-9.
(7.) Skancke MD, Auzenne TD, Tabbara SO, Mortman KD. Thoracoscopic Resection of Multiple Mullerian Cysts. Ann Thorac Surg. 2015;100(5):1898-900.
(8.) Hattori H. High prevalence of estrogen and progester-one receptor expression in mediastinal cysts situated in the posterior mediastinum. Chest 2005; 128: 3388-90.
(9.) Thomas-de-Montpreville V, Dulmet E. Cysts of the posterior mediastinum showing mullerian differentiation (Hattori's cysts). Ann Diagn Pathol 2007; 11: 417- 20. Epub 2007 Sep 17.
Ronald Mowad, MD; Navdeep Singh Samra, MD; Vyas Rao, MD
Dr. Mowad is a PGY4 resident in general surgery at LSUHSC-Shreveport; Dr. Samra is an assistant professor of trauma/acute care surgery at LSUHSC-Shreveport; Dr. Rao is an associate professor of cardiothoracic and vascular surgery at LSUHSC Shreveport.
Caption: FIGURE 1: Posteroanterior chest radiograph demonstrating a left-sided posterior mediastinal mass
FIGURE 2: CT of thorax demonstrating a left paravertebral mass
Caption: FIGURE 3: Pathology: There is a benign cystic inclusion lined by cuboidal to columnar cells with Mullerian differentiation showing ciliated columnar, secretory, and intercalated cells. The cyst has a thin wall supported by fibrous stroma with an absence of endometrial stroma and hemosiderophages. This is WT-1, ER, PR, PAX-8 and CK-7 immunoreactive. No atypia is present. Findings are consistent with Mullerian cyst.
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|Author:||Mowad, Ronald; Samra, Navdeep Singh; Rao, Vyas|
|Publication:||The Journal of the Louisiana State Medical Society|
|Date:||Mar 1, 2017|
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