JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
follow-ups. 4-6 Skancke published a novel report demonstrating bilateral Müllerian 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 Müllerian cyst. In 2005, his pathology files from1996-2004were examined, and of 19mediastinal cysts, three (16%) of the cysts demonstrated Müllerian degeneration. 8 De Montpreville published a study in 2006 examining 163 mediastinal nonneoplastic cysts discovering nine (5.5%) cysts with Müllerian 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.
FIGURE 1: Posteroanterior chest radiograph demonstrating a left-sided posterior mediastinal mass
CONCLUSION
Based on a review of the literature, it is likely that the Müllerian cyst has historically been underdiagnosed until recently. Although it is a distinctly different entity on a pathological level, the management of the Müllerian 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.
FIGURE 2: CT of thorax demonstrating a left paravertebral mass
FIGURE 3: Pathology: There is a benign cystic inclusion lined by cuboidal to columnar cells with Müllerian 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 Müllerian cyst.
44 J La State Med Soc VOL 169 MARCH/APRIL 2017
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