Splenic Radiotherapy in Refractory Immune Thrombocytopenic Purpura

Introduction

Immune thrombocytopenic purpura (ITP) is an acquired bleeding disorder that causes autoantibody-mediated platelet destruction and alters their production in the bone marrow. ITP is a complex process in which both cellular and humoral immunity are involved.

ITP is defined as the presence of isolated thrombocytopenia (peripheral platelet count of <100x10⁹/L), with no associated clinical conditions, arising as a diagnosis of exclusion. Currently, three phases of disease are described: 1. Recently diagnosed ITP (<3 months of diagnosis), 2. Persistent ITP (3-12 months of diagnosis) and 3. Chronic ITP (one that lasts >12 months and/or is refractory to treatment).

Currently, the standard of care in newly diagnosed patients is corticosteroid therapy, mainly with prednisone (dexamethasone or methylprednisolone may be used too); treatment based on anti-D IV or IVIG administration is also an option, nonetheless of the previously mentioned therapies, there are many second-line drugs that have given successful results such as: azathioprine, cyclosporine, cyclophosphamide, mycophenolate mofetil, rituximab, romiplostim and eltrombopag; the last two medications showing to modify the therapeutic approach, and in very specific cases, they both have lead to prevent splenectomy, regarded as potentially curative.

Case Report

We report the case of a 44-year-old female patient, with no relevant medical history regarding the actual disorder, presenting with sudden onset of spontaneous bruising on limbs, associated with excessive bleeding while a dental procedure was being performed. She was diagnosed with Immune Thrombocytopenic Purpura, and treatment began as all guidelines dictate, with corticosteroid therapy; however splenectomy was performed due to first-line treatment failure and high risk of early relapse. The patient was re-admitted due to post-splenectomy relapse, autoimmunity tests were done, and they resulted positive for Systemic Lupus Erythematosus, with anti-nuclear and anti-DNA antibodies. Given the poor response to previously administered treatments, we decided to perform a scintigraphy and a SPECT/CT that revealed three accessory spleens (Fig. 1); we manage to send the patient to radiotherapy (20 sessions of 10 cGy each) in order to directly radiate those spleens, obtaining complete response, with normalization of platelet count, for about six months.

Figure 1:

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Absence of spleen due to splenectomy. There are three abnormal zones marked by radiotracer in the left upper quadrant.

Figure 1:

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Absence of spleen due to splenectomy. There are three abnormal zones marked by radiotracer in the left upper quadrant.

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Months later, she relapsed once again, and we decided to perform another SPECT/CT that showed five more accessory spleens, found in stomach and omentum (Fig. 2). At this moment, the patient is receiving 500mg of micophenolate mofetil every 24 hours and 40mg of dexamethasone for four days each month, keeping her stable with a platelet count oscillating between 70,000 - 80,000mm³.

Figure 2:

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Evidence of five accessory spleens.

Figure 2:

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Evidence of five accessory spleens.

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