Miniature Palpebral Plexiform Neurofibroma in Neurofibromatosis Type 2

A 27-year-old woman with well-documented neurofibromatosis 2 developed a soft, painless, nodular lesion on the skin surface of the left upper eyelid over 2 years. Following excision, histopathology revealed a plexiform neurofibroma with intradermal nodules comprised of benign round and spindle cells that reacted diffusely with immunohistochemical stains SOX-10 and S100. A subset showed focal reactivity for neurofilament and CD34. A perineurium surrounded each nodule with cells staining positively for markers EMA (epithelial membrane antigen) and GLUT1 (glucose transporter 1). Plexiform neurofibromas are rare tumors that occur in 5%-15% of patients with neurofibromatosis 1. Cutaneous abnormalities in neurofibromatosis 2 have not been widely studied although reports have described schwannomas, plexiform schwannomas, and occasional neurofibromas. Plexiform neurofibromas in neurofibromatosis 2 have rarely been illustrated and the current case represents a unique bona fide eyelid example to date.

Apocrine Cystadenoma of the Eyelid, a Rare Neoplasm: Expanded Immunohistologic Profile

An 83-year-old woman experienced the slow enlargement of a right lower eyelid mass. Histopathologic examination of the excised tissue showed a mucin-filled cystic tumor emanating from an apocrine bilayer that displayed bleb-like apocrine decapitation secretion. The outer flattened myoepithelial layer of the bilayer reacted with immunohistochemical stains for smooth muscle actin and calponin. In foci, the tumor exhibited a cribriform architecture with small pockets of mucin. Tumor cells were reactive for cytokeratin 7, Gross Cystic Disease Fluid Protein 15 (BRST-2), estrogen and progesterone receptors, androgen receptors, mammaglobin, epithelial membrane antigen, and GATA3. Ki67 showed a very low proliferation fraction. The lesion exemplifies the fourth instance of an eyelid apocrine cystadenoma in the literature.

Pigmented Inflamed Seborrheic Keratosis of the Bulbar Conjunctiva

A 57-year-old Black man presented with the recent onset of a pigmented temporal epibulbar lesion. As pigmentation of conjunctival epithelial lesions is correlated with complexion pigmentation, the lesion was presumed to represent a pigmented ocular surface squamous neoplasia (OSSN). Excisional biopsy, however, revealed a pigmented conjunctival seborrheic keratosis, a rare occurrence. The lesion lacked cytologic atypia. Intralesional processes of dendritic melanocytes were demonstrated by hematoxylin-eosin and Melan-A stains. Melanophages also contributed to clinical pigmentation. Subepithelial lymphocytic infiltration, elevated Ki67 proliferative rate, prominent mitotic activity, and subtle spongiosis afforded evidence of inflammation rather than malignancy in a lesion devoid of cytologic atypia.

Eccrine Cyst (Hidrocystoma) of the Inner Canthus: A Rare Entity With Immunohistologic Confirmation

A small ruptured cyst was excised from the left inner canthus of a 68-year-old woman. Histopathology displayed a cyst lined by a double layer of cuboidal epithelium and filled with amorphous material. The lining cells were strongly positive for cytokeratins 5/6 and 14, with weak reactivity with cytokeratin 7. These findings were identical to those in a single previous report of an eccrine cyst of the eyelid, making this the second example of a bona fide eccrine hidrocystoma of the eyelid.

Solitary Intratarsal Blue Nevus

A 42-year-old woman presented with a small pigmented lesion of the palpebral conjunctiva that had been present for a few months. Because of the possibility of melanoma, the lesion was resected. Microscopic examination displayed an intratarsal blue nevus at the level of the meibomian glands comprised of bland nonpigmented and pigmented cells that enveloped a sebaceous gland and its ducts. The cells were of admixed spindle and epithelioid configuration and were immunoreactive for Melan-A. The Ki67 proliferative marker was negative in these cells, contrasting with the epithelium of the overlying conjunctiva and the sebaceous ducts, and thereby militating against the diagnosis of melanoma. Clusters of melanophages were also present. Although an intratarsal blue nevus has been described as a component of a combined nevus, the current lesion demonstrates the occurrence of a sole tarsal blue nevus. Palpebral pigmented lesions should be customarily excised because many are melanomas.

Targeted Neoadjuvant Intra-arterial Chemotherapy in Lacrimal Gland Adenoid Cystic Carcinoma: A Histological Correlation Using Apoptotic Tumor Markers

Neoadjuvant intra-arterial cytoreductive chemotherapy is used for the treatment of lacrimal gland adenoid cystic carcinomas (ACC) to improve outcomes in this condition with an otherwise dismal prognosis. We share our experience in the management of an advanced case of ACC using a novel, highly targeted intra-arterial cytoreductive chemotherapy delivery technique involving both the internal and external carotid circulation, with an attempt to correlate the effect histologically. Refinement of the chemotherapy delivery using the tumor's vascular anatomy and appropriate blood vessel selection may lead to future globe sparing procedures without compromising survival.

Epibulbar Subconjunctival Apocrine Hidrocystoma

Apocrine hidrocystomas are benign cystic tumors derived from apocrine sweat glands; they are most commonly located in the skin of the head and neck regions. Ophthalmic occurrences characteristically appear at the lash line and canthi of the eyelid, although rare instances have been described in the conjunctiva, caruncle, and orbit. The authors describe an exceptional instance of a mobile epibulbar subconjunctival apocrine hidrocystoma in a 57-year-old woman without a history of previous ocular injury or surgery. Histopathology of the excised specimen displayed an empty cyst lined by a double layer of cuboidal epithelium with the inner layer exhibiting periodic acid-Schiff-positive apical decapitation secretion. Confirmatory immunohistochemistry included reactivity with cytokeratin-7, smooth muscle actin, D2-40, and CDGFP-15.

Osseous Metaplasia of the Eyelid in a Child

Osteoma cutis is a term applied to bone formation in the dermis or subcutaneous tissue. It is deemed primary when occurring de novo without prior disease or secondary when associated with pre-existing inflammation, neoplasia or trauma. The authors describe a longstanding focal calcified and ossified lesion of the upper eyelid in a healthy 10-year-old girl along with a sterile corneal ulcer. The lesion most likely represented an ossified tarsal cyst or chalazion.

Conjunctival Exophytic Schneiderian-type Papillomas: A Rare Occurrence

Conjunctival papillomas are common tumors that exhibit an exophytic growth pattern, comprised of multiple filiform fronds of squamous epithelium that contain fibrovascular cores. The inverted (endophytic) variety of papilloma, often termed "Schneiderian," rarely occurs on the conjunctiva, with only 15 cases reported to date. Endophytic and exophytic papillomas are well described arising in the sinonasal Schneiderian epithelium where a low rate of malignant transformation may occur in the endophytic type; malignant transformation in exophytic sinonasal papillomas is exceedingly rare. The authors describe 2 cases of exophytic conjunctival papillomas with the morphology of a sinonasal or Schneiderian-type papilloma. Both were pink, sessile acquired growths in women in the sixth decade of life involving the inferior conjunctival fornix or nasal limbus. Nonkeratinizing squamous epithelium along with numerous goblet cells, intraepithelial mucinous cysts, and microabscesses were present. Immunohistochemistry showed reactivity for cytokeratin 7 and wild-type staining for p16 and p53, paralleling the findings in common conjunctival papillomas; both were also driven by low-risk human papillomavirus.

Orbital and Eyelid Inflammation With "Muciphages" and Extravasated Mucin From an Ethmoido-orbital Mucocele

A 22-year-old woman presented with an acute compressive optic neuropathy due to a ruptured ethmoido-orbital mucocele. She underwent urgent orbital decompression and drainage of the mucocele via an endoscopic approach. Postoperatively, her course was complicated by an orbital compartment syndrome supervened, exhibiting severe eyelid edema caused by infiltration with mucin and mucin-containing macrophages ("muciphages"). Biopsy of the eyelid showed infiltration with "muciphages," macrophages laden with extravasated mucinous material. This is the first report that documents the clinical and histopathologic course of orbital inflammation following mucocele extravasation into the orbit and eyelids.

Pseudopemphigoid: Sarcoidosis presenting as cicatricial conjunctivitis with symblepharon

Conjunctival involvement in sarcoidosis is commonly characterized by epibulbar nodules or follicular conjunctivitis. The authors describe an apparently healthy woman who developed extensive monocular cicatricial conjunctivitis with symblepharon. The array of conditions presenting with cicatricial conjunctivitis was considered, with mucous membrane pemphigoid leading the diagnostic possibilities. Conjunctival biopsy disclosed the non-infectious, non-caseating granulomas of sarcoidosis and a systemic evaluation disclosed pulmonary nodules and hilar lymphadenopathy. As the patient had no respiratory symptoms and an old history of hepatic steatosis, oral hydroxychloroquine and topical cyclosporin were chosen for therapy rather than systemic corticosteroids.

Aggressive esthesioneuroblastoma with divergent differentiation: A taxonomic dilemma

The authors describe an esthesioneuroblastoma (olfactory neuroblastoma) that occurred within the nasal cavity and brain in a 31-year-old man. Following excision, the tumor recurred in the left orbit and in mediastinal lymph nodes. Treatment included orbital excision and systemic chemotherapy. Histopathology showed a high-grade neuroepithelial tumor with positive immunohistochemical markers for neuroendocrine and epithelial components, an unusual combination raising issues concerning taxonomy.

Subperiosteal orbital fibroma

A patient noting a slowly enlarging bump at the orbital rim underwent surgical excision of the lesion. Pathologic examination showed a benign fibroma, a lesion that to the authors' knowledge has never been previously reported in this location.

Epibulbar conjunctival fibroma

A nodular, epibulbar mass appearing in an adult woman without antecedent inflammation or injury prompted concern for possible malignancy. Excision was performed, and pathologic examination demonstrated a conjunctival fibroma. The rarity of the fibroma and its clinical similarity to other benign or malignant tumors render its clinical diagnosis elusive.

Intraosseous hemangioma of the orbit

A case of intraosseous orbital hemangioma is reported to alert surgeons to possible intraoperative hemorrhage during excision of such a lesion. A slowly enlarging mass was excised from the orbital rim of a 49-year-old woman. The clinical diagnosis was not suspected. In retrospect, roentgenographic findings included a focal honeycombed pattern of the zygomatic bone. Surgery was complicated by persistent low-volume bleeding. Histology showed endothelial-lined blood-filled channels within the bone. Intraosseous orbital hemangioma is a rare, benign neoplasm that can often be diagnosed clinically by characteristic roentgenographic findings. Observation should be considered as a therapeutic alternative when the radiographic diagnosis is established and when ocular function is not compromised.

Endophthalmitis associated with extrusion of a ganciclovir implant

PURPOSE

To report a case of endophthalmitis with associated scleral defect after intravitreal positioning of a ganciclovir implant.

METHOD

Interventional case report. A 39-year-old woman developed acute endophthalmitis 1 month after insertion of a ganciclovir implant. The eye was enucleated.

RESULTS

Pathologic examination of the enucleated globe revealed an intrascleral location of the implant suture tab and a vitreous abscess.

CONCLUSION

Intraocular infection resulted from a scleral gap containing a foreign body (surgical implant). Appropriate surgical techniques should minimize the risk of ganciclovir implant extrusion.

Effect of fibrin bandage fibrinogen concentration on blood loss after grade V liver injury in swine

OBJECTIVE

To determine the effect of fibrinogen concentration of dry fibrin bandages on blood loss after grade V liver injury.

METHODS

Twenty-four pigs were used. Grade V liver injuries were induced and treated with dry fibrin bandages containing 0, 4, 8, or 15 mg fibrinogen/cm2. Animals were monitored for 60 minutes. Blood loss, fluid use, hematological data, and hemostasis were assessed.

RESULTS

Post-treatment blood losses (mean and 95% confidence interval [CI]) were 1,560 mL (356-6,844), 372 mL (65-2,134), 225 mL (51-992), and 127 mL (22-732) in the 0-, 4-, 8-, and 15-mg groups, respectively. Only the 15-mg group had results significantly lower than the 0-mg group (p < 0.05). Blood loss was negatively related to fibrinogen concentration (p < 0.05).

CONCLUSION

Fibrinogen concentration was inversely related to blood loss after grade V liver injury. The 15-mg formulation was the only one that significantly reduced blood loss.

Different hypotensive responses to intravenous bovine and human thrombin preparations in swine

BACKGROUND

Accidental intravenous introduction of commercial bovine thrombin (BT) during use of fibrin glue may result in profound hypotension. Commercial human thrombin (HT) is now available. This study compared the effects of intravenous BT versus HT in swine.

METHODS

Swine received 30 U/kg BT, 60 U/kg BT, 30 U/kg HT, or 60 U/kg HT intravenously. Mean arterial pressure (MAP) and survival were monitored for 30 minutes. Thrombin purities and in vitro activities were examined.

RESULTS

MAP nadir was lower (p < 0.05) after BT, 27.7 +/- 3.3% (mean +/- SEM) of pretreatment MAP, compared with 41.1 +/- 3.7% after HT. Five of six animals died after 60 U/kg BT, whereas all others survived (p < 0.05). Histology suggested more severe disseminated intravascular coagulation after BT. HT was purer than BT. In vitro activities were similar.

CONCLUSION

Both BT and HT produced hypotension. HT appeared safer, because of higher purity. Regardless of source and purity, thrombin must be used with caution.

Band-shaped and whorled microcystic dystrophy of the corneal epithelium

OBJECTIVE

To report the clinical, histopathologic, and electron microscopic features of band-shaped and whorled microcystic corneal epithelial dystrophy.

DESIGN

Two interventional case reports.

PARTICIPANTS

Two patients, two eyes.

INTERVENTION

The involved area of corneal epithelium was scraped from each cornea.

RESULTS

Histopathologic examination showed microscopic vacuoles in the epithelial cytoplasm in both cases. Electron microscopic examination revealed mainly empty cytoplasmic vacuoles with scant nonspecific osmophilic material. The process recurred clinically in one patient. Changes in corneal topography are documented in one patient.

CONCLUSION

Clinical findings and pathologic studies seem nearly identical to those in the original report. No pattern of systemic disorder or medication use was found. The cause of this condition remains unknown.

Intramuscular lipoma of the eyelid

To report a unique case of intramuscular lipoma of the eyelid and to alert surgeons to this entity that simulates a common dermoid cyst. A slowly-growing mass of the upper eyelid was excised from a 62-year-old man. Histology showed mature lipocytes interspersed with skeletal muscle. To our knowledge, this case represents the first report of intramuscular lipoma of the eyelid. Lipomas, including the intramuscular variety, are common tumors elsewhere in the body. The differential diagnosis of eyelid masses should include this entity.

Effect of dry fibrin sealant dressings versus gauze packing on blood loss in grade V liver injuries in resuscitated swine

BACKGROUND

We conducted this study to determine whether the dry fibrin sealant dressing (DFSD) would stop bleeding from a grade V liver injury and to evaluate the effects of leaving the absorbable DFSD in survival animals.

METHODS

Twenty-four swine (40+/-3.0 kg) received a uniform grade V liver injury and were randomized to one of four 1-hour treatment groups: (1) gauze packing, (2) DFSD, (3) immunoglobulin G placebo dressing, and (4) no treatment. All animals were resuscitated with lactated Ringer's solution. Total blood loss (TBL), mean arterial pressure, resuscitation volume, and laboratory data were monitored for 1 hour after injury. Four swine were treated with the DFSD after grade V injury and allowed to survive for 7 or 14 days.

RESULTS

The TBL was 1,104+/-264 mL (mean +/- SEM), 544+/-104 mL, 4,223+/-1,555 mL, and 6,026+/-1,020 mL for groups 1, 2, 3, and 4 respectively. TBL in DFSD animals was less than that in animals treated with gauze packing (p = 0.06). Grade V injuries were uniform among the 1-hour groups, and no evidence of intrahepatic abscess, unusual adhesions, or hepatic vein, vena caval, or pulmonary thromboses were noted in the long-term survival animals.

CONCLUSION

In this model of grade V liver injury, blood loss with the DFSD was 51% of that observed with standard gauze packing (not statistically different). Initial survival data revealed no complications attributable to the fibrin dressing. DFSD may provide simple, rapid, and definitive hemorrhage control in life-threatening liver injuries without the need for reoperation.

Hemangiopericytoma of the lacrimal sac

Hemangiopericytoma (HPCT) rarely originates in the lacrimal sac; 7 cases have been reported previously and only 1 contained an ultrastructural study. In this article we report an additional case and review the previous reports. While the initial biopsy specimen showed nonspecific cytologic abnormalities, light and electron microscopic studies on the subsequently excised tumor demonstrated that it had a structure characteristic of HPCT. The onset of lacrimal sac HPCT occurs in a younger age group than that of HPCT of other orbital locations. The tumor may recur locally but, to our knowledge, never has been reported to metastasize from a sac location. The treatment goal is complete surgical excision.

Epibulbar granular cell tumor. Report of a case and review of the literature

BACKGROUND

The granular cell tumor (GCT) is a common, usually benign, neoplasm of uncertain histogenesis that may affect any organ in the body. It occurs rarely in ophthalmic sites, where orbital location is most frequent. The purpose of this report is to describe a unique case of an epibulbar, subconjunctival GCT in a child.

METHOD

Histopathologic examination of the excised tumor included standard and immunohistochemical staining of formaldehyde-fixed, paraffin-embedded tissue.

RESULTS

Histopathologic study showed the characteristic morphology of GCT. Immunohistochemistry was strongly positive for vimentin, weakly and partly positive for neuron-specific enolase, and negative for S-100 and HAM-56.

CONCLUSIONS

Granular cell tumor must be added to the differential diagnosis of epibulbar masses. Immunohistochemistry of the tumor in this case suggests an uncommitted mesenchymal cell origin.

Conjunctival neurilemoma. Report of 3 cases

Neurilemoma (schwannoma) of the conjunctiva is a rare ocular tumor. We report 3 cases of benign conjunctival neurilemoma occurring in women without other ocular or systemic disease. Two of these tumors arose from the bulbar conjunctiva and 1 from the tarsal conjunctiva. Immunoperoxidase staining for S-100 protein was positive in each case.

Ganciclovir intraocular implant. A clinicopathologic study

BACKGROUND

Surgical implantation of the intraocular sustained-release ganciclovir device is a safe and effective treatment for cytomegalovirus (CMV) retinitis. Previous histopathologic studies on eyes containing such implants have been limited by the necessity of removing the device before processing. Microtome sectioning of hard plastics within paraffin-embedded blocks is infeasible, and the anatomic relations of implant to eye are destroyed.

METHODS

The authors studied four eyes from three patients who had undergone implant insertion. Globes with implants in place were fixed in neutral 10% formation, embedded in methylmethacrylate, sectioned on a special microtome, and stained with hematoxylin-eosin.

RESULTS

After methacrylate embedding, the precise anatomic relations of the implant to the neighboring uveoscleral coats were preserved. In two eyes, the suture tab of the implant protruded through the sclera, exiting subconjunctivally. In two eyes, the implant was totally intravitreal. In all patients, the device was supported by fibrous tissue which emanated from a surgical coloboma of the pars plana ciliaris. Focal granulomatous inflammation adjoined suture and implant materials but no other inflammation or deleterious effects on the ocular structures were noted.

CONCLUSION

This report is the first to document the intraocular histopathology of the ganciclovir implant. The subconjunctival location, enhancing the potential for endophthalmitis, may be avoided by trimming of the suture tab close to the anchoring suture and not tying it too tightly. Methylmethacrylate embedding is a useful technique for preserving the microanatomy of intraocular implants.

Calcific phacolysis. Salvageable vision following treatment

Calcific phacolysis has been previously described histopathologically in the enucleated eyes of three patients with unilateral posttraumatic total blindness. Each eye showed dissolution of a mature cataractous lens with dispersion of calcific lens material throughout the globe. We studied a patient in whom the signs of calcific phacolysis developed 19 months following intraoperative dislocation of a cataract into the vitreous. Partial removal of calcific particles was achieved by subtotal vitrectomy and lensectomy, with subsequent penetrating keratoplasty. Corneal histopathological findings showed a deposition of calcified lens particles between Descemet's membrane and retrocorneal fibrous membrane. Despite diffuse retinal calcification, the patient's visual acuity was 20/400. To our knowledge, this is the first report of calcific phacolysis occurring after surgical dislocation of a cataract into the vitreous and wherein treatment resulted in some preservation of vision. Early diagnosis and aggressive therapy may improve the visual prognosis in this condition.

Pyogenic granuloma after transconjunctival blepharoplasty: a case report

This is the first known report of a relatively large postoperative pyogenic granuloma developing after a nonsutured transconjunctival blepharoplasty. Inflammation and separation or malapposition of the conjunctival wound edges probably permitted the lesion to proliferate in the inferior fornix. No foreign material could be implicated because no suture was used to close this incision. Additionally, Polydek suture material (braided polyester fiber) was associated with the complication of a suture tract and granuloma when used for a tarsal suspension procedure for ectropion repair in this patient.

Calcific phacolysis

BACKGROUND AND METHODS

The authors report the clinical and ocular histopathologic findings in three patients with longstanding unilateral post-traumatic blindness. After one or more decades, acute pain associated with conjunctival hyperemia and apparent keratoprecipitates or a hypopyon developed in the affected eye of each individual. Phacoanaphylaxis was diagnosed preoperatively in two patients.

RESULTS

Calcified granular lens fragments were dispersed throughout all three eyes. The anterior chamber in all patients contained extracellular calcified lens particles, but only one eye contained conspicuous macrophages. Two eyes showed elevated intraocular pressure (IOP), and in one patient calcified particles extended into a glaucomatous optic nerve head.

CONCLUSION

To the authors' knowledge, this is the first report describing a rare condition involving the intraocular dispersal of calcified lens particles after disruption of the lens capsule. The authors have designated this entity as calcific phacolysis.

Periocular xanthogranulomas associated with severe adult-onset asthma

This article describes six patients who presented, usually bilaterally, with yellow-orange, elevated, indurated, and nonulcerated xanthomatous eyelid lesions, typically extending into the anterior orbital fat, and sometimes involving the extraocular muscles and the lacrimal gland. Because the eyelids remained intact and because the process did not reach the deep orbital and perioptic connective tissues, visual acuity was well preserved. There is cosmetic morbidity and occasionally motility restriction with advancing involvement of the extraocular muscles. All patients had variably severe adult-onset asthma that required treatment with systemic prednisone and inhalants. No evidence of Erdheim-Chester disease was found in any patient, but the appearance in one patient, after 25 years of follow-up, of a separate subcutaneous necrobiotic xanthogranulomatous lesion in the mandibular region with an associated paraproteinemia, suggests that at least some of our cases might be a mild form of necrobiotic xanthogranuloma. For this reason, we would suggest repeated periodic serum protein immunoelectrophoretic studies as well as evaluation for lymphoma. Therapy probably should consist of low doses of periorbital radiotherapy coupled with high doses of corticosteroids. Should this not be successful, then systemic administration of corticosteroids with chemotherapeutic agents might be efficacious, as in necrobiotic xanthogranuloma.

Epibulbar molluscum contagiosum in acquired immune deficiency syndrome. Case report and review of the literature

BACKGROUND

While molluscum contagiosum of the eyelid skin is commonly complicated by conjunctivitis, primary involvement of the conjunctiva or cornea by molluscum lesions is exceedingly rare. The authors studied a 34-year-old man with acquired immune deficiency syndrome (AIDS) in whom multiple molluscum lesions of the lids and a single nodule of the limbus developed.

METHODS

The nodular lesion was excised from the limbus and processed for histologic examination by light microscopy. Pertinent literature concerning epibulbar molluscum contagiosum was reviewed.

RESULTS

Histopathology of the excised lesion showed molluscum bodies within the acanthotic, hyperkeratotic conjunctival epithelium with surrounding chronic, nongranulomatous inflammation. Only 10 previous cases of conjunctival or corneal primary lesions have been reported, half of which showed associated cutaneous involvement. Lesions tended to be single, noninflamed, dome-shaped, and umbilicated, often with a yellowish central core. Patients were otherwise well and ranged in age from 3 to 55 years. Simple excision was effective in eradicating the lesions.

CONCLUSION

Primary epibulbar molluscum contagiosum is rare. Although cutaneous molluscum is common in AIDS, this report is the first to document conjunctival molluscum in a patient with AIDS.

Cryptococcosis of the anterior segment in acquired immune deficiency syndrome

Cryptococcosis is a rare form of human ocular infection, usually occurring in immunocompromised patients. Unilateral or bilateral posterior segment involvement is the rule. The authors describe a unique case of intraocular cryptococcosis presenting as an iris inflammatory mass in a patient with acquired immune deficiency syndrome. Diagnosis was established by anterior chamber paracentesis and confirmed by histopathologic examination of the enucleated eye.

Microsporidial keratoconjunctivitis in acquired immunodeficiency syndrome

We describe three patients with acquired immunodeficiency syndrome who presented with a bilateral coarse superficial epithelial keratitis due to infection with the protozoal parasite Microspora, Encephalitozoon cuniculi. Despite the extent of the corneal surface disease, conjunctival inflammation was minimal. Visual acuity ranged from 20/20 to 20/200. In one patient, the keratitis was complicated by the development of a surface defect with secondary Pseudomonas species infection. All patients had a history of exposure to household pets. Standard cultures were negative. Diagnosis was established in two of the three cases based on characteristic appearance of the protozoan in conjunctival scrapings. Electron microscopy of a conjunctival biopsy specimen in one patient confirmed the species. No recognized effective treatment is available for this infection.