Elastofibroma in Ligamentum Flavum in a Patient With Symptoms of Spinal Stenosis: Yet Another Case Report

Abstract

It is with great interest that I read the article by Daum et al titled “Elastofibromatous changes in tissues from spinal biopsies. A degenerative process afflicting a small but important subset of patients operated for spinal canal compression: report of 18 cases.” This seminal article together with 2 previous case reports constitute the whole literature on the subject. I wish to share a case with striking similarities to this clinicopathological entity. Recently, I was faced with biopsy material from a significantly thickened ligamentum flavum at the level of L4-L5 of a 53-year-old man with clinical symptoms of spinal stenosis. The altered ligamentum flavum warranted a biopsy with a clinical diagnosis of suspected granulomatous process. The biopsy material consisted of whitish firm tissue measuring 1.5 × 1.5 × 0.5 cm. Hematoxylin and eosin–stained sections showed cell-poor connective (ligament) tissue with surrounding fat and striated muscle tissue. The connective (ligament) tissue focally showed a preserved parallel structure of the collagen fibers but mostly displayed degenerative changes of myxoid type with pseudocystic spaces wherein clumps of fibrinoid material were found. Scattered areas of chondroid metaplasia were seen intermingled with areas showing myxoid degeneration. No inflammation was present. Throughout the degenerative areas with a predilection for regions with pseudocystic structures, irregular thick fibers, clumps, cords, and globoid structures composed of thick eosinophilic material separated by swollen collagen were present (Figure 1). On a van Gieson–Verhoeff elastin stain, these structures stained black and displayed the morphological features of pathological elastin (Figure 2). These findings show a striking similarity to the pictures and verbal descriptions of the elastofibromatous changes in spinal biopsies presented in the article by Daum et al. Also present, both in some of the cases presented by the authors and in the case presented herein, were regularly arranged elastic tissue fibers devoid of thick, fragmented globoid clumps of elastin, representing native ligament tissue. Of note is that 4 of the 18 cases presented by the authors, in addition to having symptoms of spinal cord compression, also displayed a thickening of the ligamentum flavum. All these patients were female (age 54-76 years), whereas the patient presented here is a man of similar age. Reportedly, 2 of these patients had disc herniation/