Ann Thorac Surg 2006;81:1509-1510
© 2006 The Society of Thoracic Surgeons
Case report
Cholesterol Granuloma of the Superior Mediastinum
Heyman Luckraz, FRCS
*
,
James Coulston, MBBCh,
Ahmed Azzu, FRCS
Cardiothoracic Unit, University Hospital of Wales, Cardiff, United Kingdom
Accepted for publication March 3, 2005.
* Address correspondence to Dr Luckraz, Cardiothoracic Unit, Block C5, University Hospital of Wales, Heath Park, Cardiff, CF14 4XN UK (Email: heymanluckraz{at}aol.com).
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Abstract
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Cholesterol granuloma develops as a response to cholesterol acting as an irritant and causing giant cell formation. This more commonly affects the sinuses with no previous report in the mediastinal region. We describe such a case in a cardiac surgical patient with an incidental finding of testicular lumps.
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Introduction
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Cholesterol granuloma consists of granulation tissue where cholesterol crystals that act as a powerful irritant have provoked a foreign body giant cell formation. This is a well-recognized condition affecting the middle ear, which was first reported in 1894 [1]. It has since been described in the kidney, testis, breast, mastoid air cells, orbit, para-nasal sinuses, lung, peritoneum, subcutaneous tissues, parotid gland, liver, and spleen [2, 3]. As yet, there has been no report of this entity affecting the superior mediastinum. We describe such a case in a cardiac surgical patient.
A 74-year-old man was referred for aortic valve surgery due to significant aortic stenosis (peak gradient, 100 mm Hg). He did not have any significant past medical history of note. However, preoperative clinical examination revealed an incidental finding of bilateral testicular lumps. This was investigated further with testicular tumor markers, testicular ultrasound, and a urology review.
The ultrasound revealed an epididymal cyst on the right, and an intra-testicular mass (4 mm in diameter) on the left. Therefore, an abdominal computed tomographic scan was performed, which was unremarkable especially because there was no abdominal lymphadenopathy. A chest roentgenogram was also normal. The patient was reviewed by the urologist who believed that the testicular mass was unlikely to be due to any malignant process as the computed tomographic scan and the testicular tumor markers were within acceptable limits. The patient's preoperative lipid profile (serum cholesterol, 4.6 mmol/L; serum triglyceride, 1.4mmol/L) was not deranged.
Therefore, the patient underwent elective aortic valve replacement. A significantly enlarged and abnormal looking lymph node was found after a median sternotomy. The node was located underneath the superior edge of the right half of the split manubrium. It was 27 x 20 x 7 mm and had a brown and yellow discoloration. Clinically it was not possible to exclude a malignant process. Therefore the lymph node was excised and sent for histological analysis.
The patient underwent an uneventful aortic valve replacement, made a relatively uneventful recovery, and was discharged home 10 days postoperatively.
The histological analysis of the lymph node surprisingly showed a cholesterol granuloma and excluded any malignancy as illustrated in Figure 1.
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Fig 1. Microscopic appearance confirming the cholesterol clefts and the granuloma formation. (Hematoxylin and eosin, x4.)
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Comment
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Cholesterol granuloma is a benign condition that can present due its space occupying effect on surrounding structures and may cause bone erosion [3]. Occasionally it can mimic a mitotic lesion, thus posing a management dilemma [2, 4]. In the lung, deposition of cholesterol in the alveolar air spaces can lead to severe respiratory compromise and a condition labelled as pulmonary interstitial and intra-alveolar cholesterol granuloma.
The pathophysiologic process leading to its formation is still under debate. Some authors believe that it is related to high serum cholesterol levels [4], but in this case report the serum lipid profile was within normal limits. In the breast, the pathogenesis is linked to leakage of cholesterol from ectatic ducts leading to the foreign body giant cell reaction. In the middle ear and air sinuses, the initiation factor for cholesterol granuloma is believed to be traumatic in origin. This coupled with impaired lymphatic drainage and ventilation accounts for the precipitation of cholesterol crystals. However, the source of the cholesterol can be either from fatty degeneration from cell breakdown or as a transudate from serum [5].
The favored radiologic examination is a magnetic resonance image scan as cholesterol granuloma emits high signal intensity on both T1 and T2 weighted scans. This high signal intensity, which is due to peripheral accumulation of free methemoglobin, can be amplified by intravenous gadolinium. If there is a suspicion of malignancy, then a positron emission tomographic scan is likely to differentiate the latter from a cholesterol granuloma.
Histologically, cholesterol granuloma is characterized by the formation of granulation tissue on a background of hemosiderin, histiocytes, and cholesterol clefts either extracellular or engulfed within multi-nucleated giant cells.
In conclusion, cholesterol granuloma is a rare benign condition that can be present within any organ or tissue of the body.
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References
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- Manasse P. Ueber Granulationsgeshwulst mit Fremdkoerriesenzellen Virchows Arch 1894;136:245.
- Smith GL, Hicks P, Wujesinghe DP, Holme TC. Cholesterol granuloma of the breast presenting as an intracystic papilloma Br J Radiol 1997;70:1178-1179.[Abstract]
- Shykon ME, Trotter MI, Morgan DW, Reuser TTQ, Henderson MJ. Cholesterol granuloma of the frontal sinus J Laryngol Otol 2002;116:1041-1043.[Medline]
- Thevendran G, Al-Akraa M, Powis S, Davies N. Cholesterol granuloma of the kidney mimicking a tumour Nephrol Dial Transplant 2003;18:2449-2450.[Free Full Text]
- Hiraide F, Inouye T, Miyakagowa N. Experimental cholesterol granulomahistopathological and histiochemical studies. J Laryngol Otol 1982;96:491-501.[Medline]
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Abstract
Introduction
