Visual changes are a common presentation to the emergency department and appropriate work-up is paramount. This case shows how fundoscopy findings alone alerted the medical practitioners to a life-changing, exceedingly rare systemic illness. Preretinal haemorrhages form between the hyaloid face and the inner limiting membrane of the retina, and may occur in cases of diabetes, trauma or older age.[[1]] However, in younger patients it is an uncommon clinical finding. This is the first reported case of B-cell prolymphocytic leukaemia (B-PLL) presenting with visual symptoms.

Case report

A 39-year-old Caucasian man presented to the emergency eye clinic with left eye visual field changes. Initially it was described as a haze with shimmering lights, which then progressed to a small central scotoma (blind spot). The patient had no other associated ocular symptoms nor a history of trauma. However, on further questioning, he reported an unintended weight loss of 20 kilograms over the prior 2 months. This was attributed to a loss of appetite since starting a new medication (methylphenidate).

At presentation, his Snellen visual acuities were 6/4.5 in the right, and 6/7.5 in the left eye. The slit-lamp exam revealed a small oval-shaped pre-retinal haemorrhage inferonasal to the fovea in the left eye, as seen in the figure.

The differential diagnosis for a young patient with a preretinal haemorrhage includes trauma, valsalva retinopathy, retinal arteriolar macroaneurysm and blood disorders. As there was no history of valsalva maneuver nor hypertension, coupled with a suspicious weight loss history, further investigations were carried out. The full blood count revealed microcytic anaemia, thrombocytopenia, leukocytosis and lymphocytosis.

The blood film showed primitive atypical lymphoid cells with flow cytometry confirming a clonal population of B-cells.

Subsequent investigations with haematology included a bone marrow biopsy, cytogenetics and next-generation sequencing, leading to the final diagnosis of B-PLL with TP53 mutation. The patient has since undergone chemotherapy with rituximab and bendamustine with good clinical response.

View Figure 1.

Discussion

As mentioned previously, preretinal haemorrhages in young patients are uncommon and usually due to trauma, valsalva or malformation of the retinal vasculature.[[2]] However, in this case, further investigations revealed systemic B-PLL .

Ocular involvement of leukaemia—such as preretinal haemorrhages—can occur due to direct leukaemic infiltration or as a result of abnormal blood components, such as thrombocytopaenia and leucocytosis.[[3]] Although very uncommon, these signs can precede other systemic features.[[3]]

B-PLL is a rare, highly aggressive disorder and carries a poor prognosis. It is described as a mature lymphoid malignancy and accounts for approximately 2% of all lymphoid leukaemia only when combined with T-cell prolymphocytic leukaemia.[[4]]

B-PLL is separate from chronic lymphocytic leukaemia in several ways including physical signs, morphology, cell markers and clinical progression. B-PLL usually affects elderly patients above 70 years of age, and the common presentation involves splenomegaly without lymphadenopathy. Anaemia and thrombocytopenia are seen in at least 50% of cases.[[5]] Despite active treatment, median survival in these cases is 3 years.[[6]] It is exceedingly rare for patients to present with isolated ocular manifestations of this disease. Most reported cases are linked to chronic myelogenous leukaemia (CML)[[7]] and at time of submission this is the only case of B-PLL presenting this way.

This case highlights the importance of thorough investigative work as well as high clinical suspicion for other diagnoses when clinical history does not match presentation. In this case, the patient was diagnosed before any systemic features of the disease and was able to start treatment promptly, hopefully aiding with better prognosis.