Palpebral Lobe Research Articles

Bilateral Lacrimal Duct Cyst

Reports of lacrimal gland cysts have been rare, and mostly of small, unilateral cysts of the palpebral lobes. An unusual case of bilateral, large acquired cysts of the orbital lobe of the lacrimal glands is presented. Pathologic examination showed chronic inflammation and fibrosis of the lacrimal gland structures. We suggest that prolapse of the lacrimal glands with obstruction of the lacrimal ducts, combined with chronic dacryoadenitis, led to cyst formation.

Bilateral Lacrimal Duct Cyst

ABSTRACT Reports of lacrimal gland cysts have been rare, and mostly of small, unilateral cysts of the palpebral lobes. An unusual case of bilateral, large acquired cysts of the orbital lobe of the lacrimal glands is presented. Pathologic examination showed chronic inflammation and fibrosis of the lacrimal gland structures. We suggest that prolapse of the lacrimal glands with obstruction of the lacrimal ducts, combined with chronic dacryoadenitis, led to cyst formation.

Ocular structures in an Ordovician agnostid trilobite

Ocular structures have recently been discovered on the cephalon of an Ordovician agnostid trilobite, Oculagnostus frici (Holub, 1908). They are represented mainly by obvious palpebral lobes situated at the postero-lateral part of the genae. In addition, in one specimen there is a dome-shaped structure below the palpebral lobe. This may well be the remains of an eye, but details of its structure are indeterminate. In the other two cephala to hand there is a notch or cavity beneath the palpebral lobe, indicating that the visual surface may have been encompassed by a circum-ocular suture such that the lentiferous region normally dropped out during ecdysis. The origin of the ocular structures in Oculagnostus frici is briefly discussed. Oculagnostus n. gen. is described.

Benign Mixed Tumor of the Palpebral Love of the Lacrimal Gland: Clinical Diagnosis and Appropriate Surgical Management

The treatment of suspected benign mixed tumor (pleomorphic adenoma) of the lacrimal gland consists of wide local surgical excision of the tumor and its capsule in their entirety. The tumor should be approached routinely via a lateral orbitotomy to provide maximal exposure and allow complete removal of the lesion. However, if clinical and radiographic evidence indicates a far anterior location implying an origin in the more superficial palpebral lobe, an anterior transcutaneous approach is advantageous and preferred. The authors report an adult case of an anteriorly located benign mixed tumor of the palpebral lobe of the lacrimal gland. The authors reviewed the characteristic clinical, echographic, and computed tomographic (CT) features, offered a differential diagnosis, and described surgical removal using a cryoprobe via an anterior lid approach. An awareness of the distinctive clinical and diagnostic features of benign mixed tumor of the palpebral lobe should help to avoid the complications that ensue from an incisional biopsy or piecemeal resection through the lid, and also to avoid the need for more extensive surgery for removal of residual or recurrent tumor.

Epibulbar Choristomas Containing Lacrimal Tissue: Clinical Distinction from Dermoids and Histologic Evidence of an Origin from the Palpebral Love

Three new cases of epibulbar choristomas, all containing lacrimal tissue, are presented and compared with those reported previously in the literature. The first and second cases were unilateral, complex choristomas, consisting of ectopic lacrimal tissue, smooth muscle, and cartilage; the first case was also remarkable for the presence of lesional tissue in the peripheral cornea and evidence of progressive growth during puberty. The third case was a bilateral, complex choristoma, manifesting epibulbar lacrimal tissue, cartilage, and smooth muscle; also associated were bilateral optic nervehead colobomas and a uniocular focus of posterior scleral cartilage demonstrated by computed tomography (CT) scanning. On clinical examination, all three lesions displayed highly vascularized thickenings of the conjunctiva with diagnostically useful gelatinous elevations, which corresponded microscopically to lobules of lacrimal tissue. In addition, all three cases had the interesting diagnostic feature of superficial corneal scarring or sclerosis, with a fine vascularity adjacent to the conjunctival lesional tissue. Electron microscopy of the third case demonstrated completely normal cytoarchitecture of the lacrimal tissue. Because of the frequent presence of Müller's smooth muscle in epibulbar lacrimal choristomas, the authors propose that these lesions represent embryologic ectopias or overly extensive field effects of the palpebral lobe of the lacrimal gland.

Lacrimal Ductal Cysts

Cyst formation can occur in any location where lacrimal gland tissue is present. A new classification is proposed based on these locations: (1) palpebral lobe cysts (simple dacryops); (2) orbital lobe cysts; (3) cysts of the accessory lacrimal glands of Krause and Wolfring; and (4) cysts of ectopic (choristomatous) lacrimal glands. The characteristic clinical presentation, histopathology, and treatment of these lacrimal ductal cysts is described.

Type species of the basal Ibexian trilobite Corbinia Walcott, 1924

The type species of the eurekiid trilobite Corbinia Walcott, C. horatio Walcott, 1924, possesses very short palpebral lobes located opposite 2p glabellar lobe. The palpebral lobes of species of Eurekia Walcott and of Corbinia apopsis Winston and Nicholls, 1967, are considerably longer and located opposite 1p and 2p glabellar lobes. Corbinia is here restricted to the type species, and C. apopsis is assigned to Eurekia. Corbinia horatio occurs in the Basal Silty Member of the Survey Peak Formation of southern Alberta and appears to be confined to the lower part of the Eurekia apopsis Subzone of the Saukia Zone (basal Ibexian).

Orbital Dacryops

Two patients presented with an enlarging orbital mass that proved to be simple dacryops, a condition in which a cyst arises in the palpebral lobe of the lacrimal gland. The cyst in one patient was lined by one to two layers of relatively flat epithelial cells favoring a lacrimal gland ductal origin. In the second patient, the cyst was lined by a nonkeratinized stratified squamous epithelium with numerous goblet cells consistent with a conjunctival origin.

Benign Peripheral Nerve Sheath Tumors (Neurofibromas) of the Lacrimal Gland

Two patients, a 43-year-old woman and a 62-year-old man, developed benign peripheral nerve sheath tumors (neurofibromas) of the lacrimal gland, in the former case of the deep orbital lobe, and in the latter of the palpebral lobe. A neurogenic tumor was not seriously considered clinically in either case, because of the paucity of previous reports on the occurrence of neural tumors in the lacrimal fossa region. Instead, in the first case a benign mixed tumor was considered the most likely clinical diagnosis, whereas in the second the coexistence of a swelling in the parotid gland raised the possibilities of a lymphoid tumor or a leukemia. Due to unusual light microscopic features, transmission electron microscopy was required to secure unequivocal diagnoses. In the orbital lobe tumor, an encapsulated spindle cell proliferation without nuclear palisading but with focal areas of myxoid change suggested either a cellular benign mixed tumor or a schwannoma. The palpebral lobe lesion displayed a myxoid spindle cell proliferation that had splayed apart the ducts and acinae of the lacrimal gland, to impart the overall appearance of a benign mixed tumor. The ducts, however, were multilaminar rather than possessing the usual double cellular layer seen in classical benign mixed tumors, and the glandular units contained zymogen granules, which are typically not seen in benign mixed tumors. Electron microscopy disclosed in both lesions the presence of interrupted basement membrane material partially surrounding the tumor cells, long spacing collagen (banded basement membrane material), and poorly developed desmosomes, features compatible with a neural tumor. Neither myofilaments, tonofilaments, nor ductal-type granules sometimes observed in benign mixed tumors were discovered. The tumor cells in these cases therefore failed to demonstrate clear-cut Schwann cell characteristics (eg, continuous basement membranes, pseudo-mesaxons, tangles of cell processes), and more closely resembled perineural cells that have been described in ultrastructural studies of peripheral nerve tumors including neurofibromas of other sites.

EXCISION OF PALPEBRAL LACRIMAL GLAND FOR EPIPHORA.

Reconstruction of lacrimal drainage remains a problem in spite of refinements in surgical technique. Frequent failures can be expected in canalicular repair 1 : reanastomosis of the lacrimal sac to nasal mucosa; comminuted fractures of the medial canthal region; and tumor involvement of the medial one third of the lower eyelid. When the ensuing tearing is excessive in such conditions, various methods of reconstructing lacrimal drainage have been recommended. 2-7 Results with these generally have been inconsistent. 8,9 In 1937, Jameson 10 attacked the problem by dividing the secretory ductules of the palpebral lacrimal gland. Experience with this procedure usually results in undercorrection of the epiphora. In 1952, Duke-Elder 11 summarized experience with excision of either lobe of the lacrimal gland: Excision of the lacrimal gland, or, which amounts to the same thing, of the palpebral lobe, in the great majority of cases has no serious ill-effects. Sufficient lubrication being obtained

Nepea and the nepeids (trilobites, Middle Cambrian, Australia)∗

Abstract Nepea narinosa Whitehouse, 1939, is as yet the only known species of the Nepeidae and Nepeacea. It is based on fragmentary material unsuitable for conclusive interpretation. The census of Nepeidae as yet unpublished includes five genera and twelve species, confined to the Middle and early Upper Cambrian of Australia. All nepeids have cedariform posterior sutures, free cheeks fused into a unit, a preglabellar boss, forked ocular ridges and a pustulose test. Nepea narinosa is distinguished by its very long intergenal spines and pointed, falcate palpebral lobes provided with a doublure.

Denervation of the lacrimal gland.

THE surgical treatment of epiphora is now well established and on the whole satisfactory. A success rate of almost 90 per cent. can be expected for the operation of dacryocystorhinostomy (Stallard, 1950). There still remains a considerable number of cases where the puncta or canaliculi are strictured or absent, where the lacrimal sac is absent or grossly damaged, or where the inner canthus is severely deformed. Every clinic has its cases of chronic epiphora due to dacryocystectomy and to trauma or irradiation of the inner canthus. Although many operations, such as canaliculoplasty, conjunctivodacryocystostomy, and canaliculo-rhinostomy have been devised, they are often very time-consuming and the results are far from good. Several operations have therefore been described for diminishing the secretion of tears. The removal of the palpebral lobe of the lacrimal gland was first performed by de Wecker (1891); the operation was made classical by Axenfeld (1911), and has recently been strongly advocated by Rycroft (1956). The operation is usually successful, but the occasional complication of keratoconjunctivitis sicca mars the usefulness of this procedure. Keratitis sicca following dacryoadenectomy has been reported by Kalt (1903), Knapp (1929), and Engelking (1928), and I have personally seen two cases. It is probable that the complication is more common than would be supposed from the literature, and that the fear of transforming awet eye into a dry one accounts for the general reluctance of ophthalmologists to perform this simple operation. Strebel (1936) attacked the palpebral lobe and the secretory ducts with diathermy. Jameson (1937) divided the lacrimal ductules sub-conjunctivally, an operation which can be graded in extent. It has not been possible to trace any long-term results of this operation. Exposure of the gland to x rays has been recommended by several workers (Hensen and Lorey, 1922; Hensen and Schiifer, 1924; Treiser, 1939), and some successful cases were reported. Tikhomirov (1935) described the injection of the palpebral lobe with alcohol. Patients with epiphora do not suffer constant discomfort and when sitting quietly in a warm room in subdued illumination, have no troublesome watering. Tearing is noticed when in the cold, in a wind, in a stuffy atmosphere such as the cinema, or when concentrating on close work. It is reasonable to suppose, then, that the constant steady level of lacrimal secretion is sufficient to prevent corneal and conjunctival drying, while the reflex excess lacrimation is the main source of disability. The logical treatment would be to abolish this reflex lacrimal secretion.

THE ONTOGENY OF TRILOBITES

THE ONTOGENY OF TRILOBITES

Congenital Fistula of Lacrimal Duct

CONGENITAL fistula of the lacrimal duct is very rare, and is usually associated with other congenital anomalies (Duke-Elder, 1932, 1952; Gray, 1949; Spaeth, 1948). The epithelium of the ducts and alveoli of the lacrimal gland is derived from a series of ectodermal invaginations in the region of the superior conjunctival fornix. Early buds form the orbital portion, while secondary buds from above appear later and form the palpebral lobe at the 40-60 mm. stage of the foetus. The stalk of the ectodermal invaginations, at first solid, are later canalized (50-55 mm.). The full development of the gland occurs at about 3 to 4 yrs. The gland ducts are about twelve in number, two to five being derived from the orbital lobe, and six to eight from the palpebral lobe; they all pass through the palpebral lobe as would be expected from their development. The majority of ducts open into the lateral part of the superior fornix, but a large duct (which may be called the inferolateral duct) traverses the extreme outer end of the gland, passes just deep to the conjunctival epithelium, and opens a few millimetres lateral to and some distance below the external commissure. The case described below is that of a little girl who had a congenital fistula of the right inferolateral lacrimal duct and right dacryocystitis with no associated deformity of the external canthus or elsewhere.

Scientific Serials

American Journal of Science, November.—On New England and the Upper Mississippi basin in the glacial period, by James D. Dana. During the recent discussions concerning the unity or otherwise of the glacial epoch in North America, it has appeared that workers in the central and western portions have mostly advocated two glacial epochs, while New England geologists have been the chief advocates of unity. The author has not found any facts in New England geology that require for their explanation an appeal to two glacial epochs, but has found an explanation of the appearances which have led western geologists to that opinion. The cause of this sectional divergence is mainly meteorological. Even at the present time, the precipitation in the east is far above that of the west, and in the glacial epoch the difference must have been still greater, owing to the greater elevation of the east. The conditions of the ice-sheet in the interior being near the critical point, a small meteorological change, if long continued, might carry off the ice for scores or hundreds of miles from a southern limit, while the eastern border was all the time gaining in ice, or was making only a short retreat.—On the use of the name “Catskill,” by John J. Stevenson. Mr. Darton's suggestion that the term Catskill should be applied to the whole of the Upper Devonian period is inappropriate, since Catskill has been shown to belong to an epoch only, whereas “Chemung” carries with it the conception of those physical and biological characteristics which mark the great closing period of the Devonian.—The finite elastic stress-strain function, by G. F. Becker. This is an investigation of finite stress and strain from a kinematical point of view, and of the function which satisfies the kinematical conditions consistent with the definition of an isotropic solid. The bearing of the theory upon finite sonorous vibrations is compared with the corresponding deductions from Hooke's incomplete law.—A larval form of Triarthrus, by C. E. Beecher. Since the discovery of antennæ and other appendages of this trilobite by Mr. W. D. Matthew, it has been possible, with the new material supplied to the Yale Museum, to trace its development back to the earlier stages. Larval specimens have been found in which the thorax is undeveloped and the cephalon predominates, while the other parts are not clearly differentiated. The larva is ovate in outline. The frontal margin is marked by a convex fold of the test. The axis is annulated. Near the lateral anterior margins are two slight elevations which may represent the palpebral lobes of the eyes.