Lacrimal gland inflammation and tumours

Lacrimal Gland Disorders & Neoplasms

The lacrimal gland is situated in the lacrimal fossa of the frontal bone in the anterolateral superolateral roof of the orbit, divided by the lateral horn of the levator aponeurosis into a larger orbital lobe and a smaller palpebral lobe.

1. Acute Dacryoadenitis

• Inflammatory or infectious enlargement of the lacrimal gland.
• Clinical Presentation: Acute, painful swelling of the outer third of the upper eyelid, resulting in a characteristic S-shaped ptosis (sigmoid contour of the upper lid margin). Tender, lobulated mass palpable under the superolateral orbital rim; eversion of the upper lid reveals an enlarged, hyperaemic palpebral lobe protruding into the superior fornix. May be accompanied by preauricular lymphadenopathy.
• Etiology: Infectious (Epstein-Barr virus, mumps, CMV, Staphylococcus, Streptococcus) or Autoimmune / Inflammatory (Sarcoidosis, IgG4-related ophthalmic disease, Thyroid Eye Disease, Granulomatosis with Polyangiitis).

2. Lacrimal Gland Tumours: The "Rule of 50s"

Approximately 50% of lacrimal gland lesions are non-epithelial (orbital lymphoma, reactive lymphoid hyperplasia), and 50% are epithelial neoplasms. Of epithelial neoplasms, 50% are benign (Pleomorphic Adenoma) and 50% are malignant (Adenoid Cystic Carcinoma and others):

• Pleomorphic Adenoma (Benign Mixed Tumour):
  • Clinical Presentation: Middle-aged adults (30-50 years); slowly progressive, painless, smooth, rubbery mass in the superolateral orbit causing inferomedial globe displacement and axial proptosis over $>12\text{ months}$.
  • Imaging (CT/MRI): Well-circumscribed, homogeneous, round or lobulated mass causing smooth, well-corticated expansion and remodeling (bony scalloping) of the lacrimal fossa WITHOUT bony erosion.
  • Biopsy planning: A typical resectable pleomorphic adenoma is generally removed with its capsule intact to minimise recurrence. If the diagnosis is atypical or uncertain, a specialist plans biopsy and definitive excision together. Capsular breach increases risk, but it does not invariably transform every adenoma into carcinoma.
• Adenoid Cystic Carcinoma (ACC):
  • Most common malignant epithelial tumor of the lacrimal gland.
  • Clinical Presentation: Young to middle-aged adults; rapid progression ($<6-12\text{ months}$), severe pain (characteristic hallmark caused by early perineural invasion), diplopia, inferomedial globe displacement, and sensory hypoesthesia along the supraorbital and supratrochlear nerves.
  • Imaging: Poorly defined, infiltrative mass with destructive, irregular bone erosion of the lacrimal fossa and punctate calcification.
  • Histopathology: Cribriform ("Swiss-cheese" pattern of basaloid cells around pseudoglandular spaces), tubular, or solid sheets. Strong propensity for perineural tracking into the orbital apex and intracranial space.
  • Prognosis: Notoriously poor (10-year survival $<20\%$); frequent late haematogenous metastases to the lung and bone. Managed with radical orbitectomy/exenteration, adjuvant radiotherapy (proton beam), and intra-arterial chemotherapy.

Comparative Features of Lacrimal Gland Lesions

Infection and Tumour Boundaries

A congenital dacryocele can have an intranasal component and cause respiratory distress, especially in a neonate; urgent paediatric/ENT assessment takes priority over an observation timetable. Acute dacryocystitis needs antibiotics, with abscess drainage when indicated. Early endoscopic DCR can be appropriate in selected cases with expertise; it is not invariably necessary to wait until every inflammatory sign disappears. DCR stenting and flaps depend on anatomy and technique. Dacryops is a lacrimal-gland duct cyst, distinct from a sac mucocele. Bloody tears, a firm sac mass or atypical obstruction raise concern for tumour and require imaging/tissue planning. Adenoid cystic carcinoma has variable modern treatment, including selected globe-sparing approaches; an old fixed survival percentage or universal exenteration rule is inappropriate.

Case: a lacrimal gland mass with an uncertain label

A patient has a slowly enlarging superotemporal orbital mass with inferomedial globe displacement. A circumscribed appearance and long painless history can suggest pleomorphic adenoma, but neither finding excludes another tumour. Pain, rapid change, sensory symptoms or bone destruction alter the differential and tissue plan. Review imaging with an orbital specialist before an unplanned incisional biopsy: a suspected encapsulated adenoma requires a coordinated approach that protects its capsule, whereas suspected lymphoma may require a different specimen and treatment pathway. Tell pathology the location and working differential, and arrange fresh material when a lymphoma investigation is intended. The plan must distinguish lacrimal gland disease from lacrimal sac obstruction; performing DCR would not treat a gland mass. Explain that recurrence risk and later surveillance depend on the diagnosis, completeness of excision and any capsular disruption.