Conjunctivitis, Lipogranulomatous – Feline

Disease Description:
Definition
Lipogranulomatous conjunctivitis is an uncommonly described palpebral and subconjunctival inflammatory condition of cats.¹ It is characterized by lobulated areas of lipid deposition and granulomatous inflammation along the eyelid margin in the region of Meibomian glands and ducts.^1-3 The condition has not been reported in the dog.

Disease Description in This Species:
Etiology
The underlying etiology is unknown. A higher incidence may be present in color-dilute and white cats.³ Lipogranulomatous conjunctivitis has also been reported with ocular squamous cell carcinoma, so actinic (UV light) radiation may play a role.⁷ The most likely cause is damage to the Meibomian glands, with leakage of sebaceous material that leads to significant granulomatous inflammation.² Trauma may be the inciting cause of Meibomian gland damage, although this has not been elucidated fully.

Diagnosis
Ophthalmic Examination Findings: Typical findings include variably-sized, lobulated white, pink, cream-colored or tan eyelid masses on the conjunctival side of the eyelids. Lesions are located in the tarsal plate, in the region of the Meibomian glands and ducts.² Lesions are smooth and non-ulcerated. The cutaneous aspect of the eyelid is often normal in appearance. Affected cats often have ocular discomfort, with blepharospasm and epiphora being the most common presenting complaints. Other concurrent ocular conditions may also be present that cause discomfort, so it can be difficult to determine how much the lipogranulomatous conjunctivitis is contributing to the ocular pain.² Lipogranulomatous conjunctivitis may be bilateral or unilateral. It may affect the dorsal eyelids or both the ventral and dorsal eyelids.² Lesions limited to the ventral eyelids alone have not been reported.

Physical Examination Findings: No systemic conditions or abnormalities have been associated with lipogranulomatous conjunctivitis. This condition is thought to arise from subconjunctival release of sebaceous material from the Meibomian glands; however, the possibility of systemic lipid metabolic disorders has not been completely ruled out.²

Histopathology: Diagnosis is made most often by ocular examination, based on the classic appearance and location of the lesions. Diagnosis can be confirmed by wedge biopsy and histopathology. Histopathology shows large, clear spaces within the lamina propria that are presumed to have been filled with lipid material. These spaces are surrounded by mild to severe granulomatous inflammation.² Some mild to moderate subepithelial lymphoplasmacytic and neutrophilic inflammation may be observed but is not the predominate type of inflammation in most cases. Periglandular fibrosis is also a prominent histologic feature.

Signalment
Lipogranulomatous conjunctivitis typically occurs in middle-aged to older cats, with a reported mean age of 11.2 years.² No breed predilection has been reported but white and color dilute cats may be overrepresented.

Clinical Signs
Most cats have signs of ocular discomfort (e.g. ocular discharge, blepharospasm), although many of these cats have other concurrent ocular diseases that may be contributing to the discomfort (e.g. ventral entropion). Conjunctival hyperemia, mass-like eyelid lesions, and conjunctival swelling are common. Lesions range widely in severity. Some mildly affected cats may have 1-3 enlarged, smooth, white or pink-colored nodules (1-2 mm) on the conjunctival surface of the eyelids in the area of the Meibomian glands (Figures 1, 2). More severe lesions may appear as overlapping, severely-engorged subconjunctival lobules as large as 5 mm in diameter (Figure 3). Lesions may extend the entire length of the eyelids (Figure 4).

Etiology:
Idiopathic, unknown
Inflammation
Ultraviolet light

Breed / Species Predilection:
None, no breed signalment

Sex Predilection:
None

Age Predilection:
Mature, middle-aged
Old

Diagnostic Procedures:		Diagnostic Results:
Biopsy and histopathology of eye/ocular tissues		Granulomatous inflammation
		Inflammatory cell infiltration
		Lipid droplets in nodules

Images:

Treatment / Management:
SPECIFIC THERAPY
Medical therapy with topical antibiotics and anti-inflammatory agents (e.g. corticosteroids, nonsteroidal drugs) may be effective in mild cases.³ For severe cases and for eyes with persistent discomfort despite medical therapy, surgical resection of the lesions may be considered.⁴ Because this surgery also excises Meibomian glands, loss of some or all of the lipid component of the tear film is likely and may result in a qualitative tear deficiency.^5,6

SUPPORTIVE THERAPY
Because concurrent ocular diseases can be present, treatment of other irritating conditions is also required. Minimizing sun exposure cats may be considered in affected cats.

MONITORING and PROGNOSIS
Associated conjunctival hyperemia and mild clinical signs often respond to topical anti-inflammatory drugs, and lesions may remain static for long periods of times. Nodules do not typically disappear; however, and repeated therapy may be required. Prognosis for severely affected eyes with surgical excision is good over the short term (i.e. 4 – 21 months); however, studies with long-term follow up are lacking. Periodic monitoring (q 4-6 months) of tear film quality may be warranted with removal or damage to the Meibomian glands.⁸ In general, surgical removal of large sections of palpebral tissue can result in cicatricial entropion,⁴ although this sequela has not been reported in surgically-treated, affected eyes.

Special Considerations:
Other Resources:
VIN Message Board discussions on lipogranulomatous conjunctivitis
Proceedings articles that mention lipogranulomatous conjunctivitis
For more images see the Noninfectious Conjunctivitis – Cat slideshow in the Image Library

Differential Diagnosis:
Blepharitis
Chalazia
Conjunctival neoplasia
Eyelid neoplasia
Other types of eyelid granulomas, e.g. pyogranulomatous, foreign body reaction, fungal, etc.

References:

1. Kerlin R L: Lipogranulomatous Conjunctivitis in Cats . Vet Comp Ophthalmol, 3 Refs ed. 1997 Vol 7 (3) pp. 177-79.
2. Read R A, Lcas J: Lipogranulomatous conjunctivitis: clinical findings from 21 eyes in 13 cats . Vet Ophthalmol 2001 Vol 4 (2) pp. 93-8.
3. Stiles J, Townsend WM, Gelatt KN : Feline Ophthalmology. Veterinary Ophthalmology, 4th ed. Wiley Blackwell, Ames IA pp. 1106-7.
4. Long R D: Treatment of distichiasis by conjunctival resection. J Small Anim Pract, 14 Refs ed. 1991 Vol 23 (3) pp. 146-48.
5. Bron AJ1, Tiffany JM.: The meibomian glands and tear film lipids. Structure, function, and control. Adv Exp Med Biol 1998 Vol 438 pp. 281-95.
6. Bron AJ1, Tiffany JM, Gouveia SM, et al: Functional aspects of the tear film lipid layer. Exp Eye Res 2004 Vol 78 (3) pp. 347-60.
7. Teifke J P, Löhr C V: Immunohistochemical detection of P53 overexpression in paraffin wax-embedded squamous cell carcinomas of cattle, horses, cats and dogs. J Comp Pathol 1996 Vol 114 (2) pp. 205-10.
8. Pucker AD, Haworth KM: The presence and significance of polar meibum and tear lipids.. Ocul Surf 2015 Vol 13 (1) pp. 26-42.

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