Sir,

We report an unusual case of low-grade systemic lymphoma presenting with nasolacrimal duct obstruction secondary to a localised aggressive transformation in the lacrimal sac. There was a good response to treatment with surgical excision and chemotherapy combined with rituximab.

Case report

A 64-year-old female presented with a 1-year history of right epiphora. Lacrimal syringing confirmed obstruction at the distal canaliculus implying common canaliculus block with no associated palpable mucocele/masses. She underwent an external right dacryocystorhinostomy; however, intra-operatively, the lacrimal sac wall was abnormally thickened, and a biopsy was performed.

Histology revealed an aggressive high-grade diffuse large B-cell lymphoma (DLBCL, Figure 1). Physical examination, biochemical tests, MRI, and staging CT scans were all normal, with no evidence of lymphomatous involvement elsewhere. A subsequent bone marrow biopsy revealed low-grade non-Hodgkin's lymphoma (Figure 2).

Figure 1
figure 1

Lacrimal sac histology of B cells stained with MIB-1 (arrow), an immunohistochemical marker of cell proliferation, demonstrating very high (almost 100%) proliferation characteristic of high-grade NHL.

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Figure 2
figure 2

Bone marrow biopsy showing low-grade sinusoidal small B-cell infiltrate (arrow) very typical of marginal zone lymphoma. The B cells have been stained with CD20 (B lymphocyte surface antigen B1), which is strongly positive on almost all B-cell lymphomas and has a role in the regulation of B-cell proliferation.

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Treatment was commenced with chemotherapy comprising of six cycles of vincristine, cyclophosphamide, doxorubicin, prednisone, and rituximab (R-CHOP) over 4 months. She responded well towardstreatment, and is currently awaiting adjunct maintenance rituximab. She remains systemically well with no symptoms of epiphora.

Comment

Lymphomas involving the lacrimal sac are rare and usually occur secondary to systemic lymphoreticular malignancy.1 They typically present with medial canthal swelling, classically extending above the medial canthal ligament, and epiphora. Our patient was unusual as her only symptom was persistent epiphora, with no associated masses.

Although orbital and adnexal lymphomas are commonly of the low-grade MALT subtype, there is a marked over-representation of high-grade DLBCL occurring within the lacrimal sac.2 This could potentially be explained by localised transformation from the MALT lymphoma subtype possibly due to persistent antigenic stimulation arising from the frequently chronic nature of infections of the lacrimal sac.3

Radiotherapy is considered the standard treatment for indolent/localised lymphoma.4 In our patient, due to the systemic disease and aggressive subtype, chemotherapy was considered to be a better first-line treatment. Over the last decade, survival rates have improved with the addition of rituximab to CHOP chemotherapy.4 This is a CD20-specific monoclonal antibody that focuses on pre-differentiated B cells. Its exact mode of action is unclear, but it is thought to downregulate the B-cell receptor and induce apoptosis of CD20+ cells.

Our case highlights the need for consideration of unusual presentations of aggressive lymphomas in seemingly trivial complaints such as epiphora, and documents the lacrimal sac as a site for aggressive malignant transformation of an otherwise low-grade systemic lymphoma.