Ghassan Ayish Alyahya MD, DO, FRCS Eye Pathology Institute University of Copenhagen Frederik V's Vej 11-1 DK-2100 Copenhagen Ø Denmark Tel: + 45 35 32 60 70 Fax: + 45 35 32 60 80 Email: email@example.com
Purpose: To analyse clinical referral diagnoses and the location of lesions with histologically verified lacrimal gland tissue occurring outside the fossa of the lacrimal gland.
Methods: Sections of lesions excised from areas outside the fossa of the lacrimal gland containing lacrimal gland tissue on histological examination were collected from the files of the Eye Pathology Institute, Copenhagen, Denmark. Specimens spanned a period of 50 years. Sections were re-examined and referral data on location and clinical diagnosis were compared with histological findings.
Results: A total of 120 lesions were collected. Of these, 59 (49%) consisted of prolapsed lacrimal gland. The remaining 61 (51%) lesions contained ectopic lacrimal gland tissue, either as part of a complex choristoma in 38 (32%) cases, or as solitary ectopic lacrimal gland tissue in 23 (19%) cases. The majority (97; 81%) of lesions had been located at the temporal epibulbar conjunctiva and included mainly prolapsed lacrimal gland and complex choristoma. The clinical referral diagnoses covered a wide spectrum of lesions. The most frequent clinical diagnoses were non-specific tumour (35%), non-specific cyst (18%) and dermoid (11%). Of the 61 lesions containing ectopic lacrimal gland tissue, only two had been preoperatively diagnosed as such and only two of the 59 lesions with prolapsed lacrimal gland had been correctly diagnosed.
Conclusions: Prolapsed palpebral lobe of the lacrimal gland was the most common lesion and, as expected, the prime location was the temporal conjunctiva. Despite this location, the referring clinical diagnosis was often wrong or non-specific. Surgeons seem to have been unaware of the various clinical manifestations of extrafossal glandular tissue, particularly when excising lesions in the upper temporal region of the conjunctiva. Surgical intervention in this location may jeopardize the excretory ducts of the lacrimal gland and may consequently lead to dry eye and thus should be avoided when the typical clinical appearance of prolapsed lacrimal gland is encountered.
The secretory lacrimal apparatus is composed of the main lacrimal gland located in the orbital lacrimal fossa, with its palpebral lobe at the temporal side of the superior fornix, and two further sets of accessory lacrimal glands, the glands of Krause and the glands of Wolfring (or Ciaccio).
Similar accessory glands are occasionally seen deep in the caruncle (Wolff 1954) and correspond to the lacrimal gland of the nictitating membrane in animals.
The palpebral portion of the lacrimal gland may prolapse into the subconjunctival space at the upper temporal bulbar conjunctiva and may consequently be misdiagnosed as prolapsed orbital fat, dermolipoma, lacrimal gland tumour or ectopic lacrimal gland tissue (Smith & Petrelli 1978; Beer & Kompatscher 1994). Consequently, prolapsed lacrimal gland tissue may be surgically removed.
In this study we reviewed the clinical and histological features of a large series of ectopic lacrimal gland tissue to correlate preoperative clinical diagnosis with the final histological diagnosis.
Material and Methods
Archived material from the Eye Pathology Institute spanning the last 50 years (1953–2002) was screened for histologically identified lacrimal gland tissue excised from sites in the eye region outside the lacrimal gland fossa. A total of 156 specimens were retrieved.
Thirty-six lesions containing accessory lacrimal glands were excluded from the study. These lesions were seen incidentally in specimens of eyelid or caruncular tumours.
Sections of the remaining 120 paraffin-embedded specimens were stained with haematoxylin-eosin (HE) and re-evaluated microscopically for the presence of lacrimal gland tissue. Referral data on each case, including the location of the lesion and the preoperative clinical diagnosis, were compared with the histological findings. The lesions were subdivided into two categories according to location and histological characteristics:
(1) prolapsed lacrimal gland, and
(2) ectopic lacrimal gland tissue, either as part of a complex choristoma, or as solitary ectopic lacrimal tissue.
The distribution of the 120 studied cases is shown in Table 1. Fifty-nine lesions (49%) were found to contain prolapsed lacrimal gland. The remaining 61 (51%) lesions contained ectopic lacrimal gland tissue, either as part of a complex choristoma (38; 32%) or as solitary ectopic lacrimal gland tissue (23; 19%). One case of complex choristoma was seen in association with systemic manifestations of linear nevus sebaceous syndrome.
Table 1. Distribution of lesions containing lacrimal gland tissue outside the lacrimal fossa.
Type of lesion
Prolapsed lacrimal gland
Choristoma with ectopic lacrimal gland tissue
Solitary ectopic lacrimal gland tissue
Most of the lesions with prolapsed lacrimal gland (54; 92%) were, as expected, located at the upper temporal bulbar conjunctiva (Fig. 1A). The majority of complex choristoma with ectopic lacrimal tissue (31; 82%) were located at the temporal epibulbar conjunctiva (Fig. 1B). Lesions with solitary ectopic lacrimal gland tissue also showed a predilection for the temporal epibulbar conjunctiva (12; 52%) (Fig. 1C).
Thirteen lesions were located within the orbit but outside the lacrimal fossa. Eight of these contained ectopic lacrimal gland tissue, either as part of a complex choristoma in two lesions (Fig. 1B), or as solitary ectopic lacrimal gland tissue in six lesions (Fig. 1C). The remaining five orbital lesions were prolapsed orbital lobes of the lacrimal gland (Fig. 1A).
The clinical referral diagnoses are shown in Table 2. The majority (83; 69%) had been designated as non-specific tumours, non-specific cysts and dermoids.
Table 2. Correlation between referral clinical diagnoses and histological diagnoses.
Prolapsed lacrimal gland
Solitary ectopic gland
Main lacrimal gland
Ectopic lacrimal gland
Of the 61 lesions that contained ectopic lacrimal gland tissue, only two cases had been clinically diagnosed as such (Table 2). Prolapsed lacrimal gland lesions showed the same pattern, with only two lesions out of 59 having been correctly diagnosed clinically (Table 2).
Subconjunctival prolapse or herniation of the palpebral lobe of the lacrimal gland is quite frequently observed, but is often misdiagnosed as epibulbar choristoma, lipodermoids or herniated orbital fat (Smith & Petrelli 1977; Beer & Kompatscher 1994) and surgically removed. In our series, nearly half the lesions examined (59; 49%) were prolapsed lacrimal glands (Figs. 2A, B). Of these lesions, 54 represented prolapse of the palpebral lobe and had been excised from the upper temporal conjunctiva (Fig. 1A). The remaining five cases involved posterior prolapse of the orbital lobe. These figures correspond to reports in the literature, where prolapse of the palpebral lobe is much more common than the prolapse of the orbital lobe (Smith & Petrelli 1978).
Prolapsed lacrimal glands had been excised under a wide variety of incorrect clinical diagnoses in our series (Table 2). The majority (43 cases) had been preoperatively misdiagnosed as non-specific tumours (Figs. 2A, B), non-specific cysts or dermoids. Only two cases had been preoperatively correctly diagnosed as prolapsed lacrimal gland. This indicates that the surgeons involved were unaware of this clinical condition. Such unawareness can lead to unnecessary surgical removal of prolapsed lacrimal gland tissue, which should be dealt with by re-positioning of the gland.
In our material, 61 (51%) lesions contained ectopic lacrimal gland tissue. These represented either a single tissue choristoma presenting as solitary ectopic lacrimal gland tissue (23; 38%) or part of a complex choristoma containing other choristomatous tissues (38; 62%) (Figs. 2C, D). In their review of 35 lesions with ectopic lacrimal gland tissue, Pfaffenbach & Green (1971) found more solitary ectopic lacrimal gland tissue lesions (54%) than complex choristoma lesions (46%). This difference in the figures may be due to the small number of cases studied.
The majority of cases with ectopic lacrimal gland had been clinically diagnosed as non-specific tumours (Figs. 2C, D). Dermoids were the second most common preoperative diagnosis. Pfaffenbach & Green (1971) examined 31 cases of ectopic lacrimal glands. Of these, dermoids and lipodermoids were the clinical impression in 17 cases, whereas non-specific tumour was diagnosed in only three patients (Pfaffenbach & Green 1971).
Complex choristoma with ectopic lacrimal gland tissue is commonly seen as an isolated lesion. Rarely, it may be associated with other systemic manifestations, as in linear nevus sebaceous syndrome (Duncan et al. 1998). In our series only one case of complex choristoma was found in association with linear nevus sebaceous syndrome.
Orbital ectopic lacrimal gland tissue as a solitary mass or as a complex choristoma is relatively uncommon. Sakurai et al. (1997) reviewed the literature and found only 22 cases reported worldwide. Since then, two additional cases have been reported (Shields et al. 1997; Kao et al. 2000). In our series, eight cases of orbital ectopic lacrimal tissue were found. This figure is relatively high for a country with a population of 5 000 000, compared with 24 cases reported in the whole world. This relatively high figure in Denmark may be due to the fact that many cases are not registered worldwide and because of incomplete clinical data.
The prevalence of non-specific clinical diagnoses may indicate that surgeons are unaware of the clinical diagnosis of such conditions. This is of particular interest when surgeons are dealing with masses located at the upper temporal bulbar conjunctiva. In our series the majority of lesions excised from extraglandular sites had been located in this area (97 cases), and the majority of these (54 cases) represented the prolapsed or herniated palpebral lobe of the lacrimal gland, for which surgery could have been avoided or altered. Lack of awareness that these lesions might be prolapsed glands may lead to surgical excision jeopardizing the excretory ducts of the lacrimal gland, resulting in dry eye.
The authors give special thanks to the Department of Ophthalmology, Aalborg Hospital, Denmark, for providing the clinical photographs. The study was supported by Lundbeckfonden.