Salzmann's nodular degeneration is a clinical entity with varied etiology.12345 Vannas5 and Houber6 reported the possibility of its recurrence after primary surgical treatment. An extensive literature search could reveal only few reports of a possible recurrence of this clinical condition.5678 We report two histopathologically proven cases of recurrence of Salzmann's nodular degeneration following keratoplasty; one recurring after lamellar and the other following penetrating keratoplasty.
A forty-year-old male presented to the cornea service of our centre with a history of painless, progressive diminution of vision in both the eyes, for 3 years. According to previous medical records, he had undergone lamellar keratoplasty in both eyes, 22 years ago. The previous histopathologic records of the lamellar corneal button had shown features of Salzmann's degeneration. In the initial postoperative period, the graft remained clear, with good visual acuity. Then he was lost to follow up and reported to our centre 1 year back, with progressive diminution of vision. The best-corrected visual acuity (BCVA) was 7/200 in the right eye and 3/200 in the left eye. Slit lamp biomicroscopy showed signs of healed trachoma, with 6 and 7 nodules in the cornea of the right eye and left eye, respectively. A faint scar of previous lamellar keratoplasty with ill-defined interface was visible. There was presence of a linear scar in the upper palpebral conjunctiva, along with few concretions in both the eyes, suggestive of healed trachoma. The values of Schirmer's I were 12 and 14 in the right and left eye respectively and the tear breakup was instantaneous. Pachymetry showed a central corneal thickness of 710 µ in the right eye and 740 µ in the left eye. Fundus was not clearly visible by the ophthalmoscope (direct and indirect). B scan ultrasonography for posterior segment and electrophysiological tests were within normal limits, in both the eyes.
A repeat lamellar keratoplasty was performed in the right eye (7.5 mm/8 mm). Postoperatively, the graft showed good apposition with graft clarity and at 6 weeks follow-up, his BCVA was 20/120 on Snellen's acuity chart. The histopathologic evaluation of the host button revealed an atrophic epithelium with a nodule identified superficial to stroma, consisting of dense collagenous tissue, which stained well with Masson trichrome. Bowman's membrane was absent and replaced by eosinophilic material that did not stain for reticulin, amyloid or elastic fiber [Figure 1].
A 24-year-old male presented to us with a history of progressive diminution of vision for 12 to 14 months in the left eye and for 4 to 5 years in the right eye. Six years ago, he had been diagnosed to have bilateral Salzmann's nodular degeneration, for which penetrating keratoplasty was performed in the left eye.
On examination, the BCVA was 10/120 in the right eye and 3/200 in the left eye. On slit lamp biomicroscopy, there was evidence of healed trachoma on lid eversion in both the eyes, in the form of a faint linear scar in the upper palpebral conjunctiva, along with few concretions. There was presence of a superficial corneal haze with 6 nodules in the right eye and 5 nodules in the left eye, limited to the anterior stroma. The values of Schirmer's I were 15 and 12 in the right and left eye respectively and the tear breakup was instantaneous. Pachymetry showed a central corneal thickness of 495 µ in the right eye and 513 µ in the left eye. Fundus was not clinically visible and specular microscopy was not possible due to corneal haze and irregular surface due to the presence of nodules.
B-scan ultrasonography for posterior segment and electrophysiological tests were within normal limits in both the eyes. Lamellar keratoplasty was performed in the left eye (8 mm/8 mm). The histopathologic evaluation of the host tissue revealed features of Salzmann's degeneration.
Salzmann's nodular degeneration is a well-defined clinical entity. The disease usually involves the anterior stroma, so the results have been very good with lamellar keratoplasty.7 However, there are reports where penetrating keratoplasty has been performed, yielding equally good results.7
Recurrence of Salzmann's nodular degeneration following corneal transplantation is uncommon [Table 1]. Severin7 reported a case of Salzmann's degeneration which later recurred in the donor cornea as an opacity, nine years after penetrating keratoplasty. Considering this clinical finding to be a precursor of Salzmann's degeneration, he regarded it as a recurrence of the disease. Frising8 reported a case of Salzmann's degeneration manifesting 2 years after performing keratoplasty for non-specific hyaline degeneration of the cornea, considered to be early Salzmann's degeneration. The earlier reports of recurrence of Salzmann's degeneration were based on clinical evidence. However, in the present report, both cases of recurrence of Salzmann's degeneration were confirmed histopathologically [Table 1].
Salzmann's degeneration is mostly confined to the superficial stroma, hence, it can be removed completely by partial thickness lamellar dissection of the cornea. However, rarely has the disease been reported to recur, which can be attributed to the chronic irritation of the cornea as a result of poor epithelial protection owing to altered ocular surface.5 This provides the stimulus for the overgrowth of fibroblasts, eventually leading to the formation of nodules. Another factor could be chronic exposure to certain climatic conditions.58 It is believed that exposure to sunlight and environmental irritants can cause hyaline changes in the nodules by precipitation of ground substance onto the collagen fibers. Immune reaction in the graft can also contribute to the recurrence of this nodular degeneration.7 This leads to surface alterations with dryness of the eye and epithelial defects, which may lead to a scar in Bowman's membrane resulting in a flat opacity, eventually giving rise to characteristic nodules of Salzmann's degeneration after a few years.
The two cases reported, illustrate the rare recurrence of Salzmann's nodular degeneration following keratoplasty. An unstable tear film due to chronic trachoma and continued exposure to dust, wind and sunlight, probably were the predisposing factors.
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