Unremitting pyrexia, pancytopenia, hepatosplenomegaly, and extreme hyperferritinemia.

A 52-year-old woman presented with unremitting pyrexia reaching 40°C. There was progressive weight loss and jaundice. A series of investigations failed to give a diagnosis, and because of rapid deterioration she was referred for management. On admission, she was moribund, with a fever of 40°C. There was marked pallor and jaundice. Abdominal examination showed gross hepatomegaly and splenomegaly (22 cm and 6 cm below the costal margin, respectively). A full blood count showed hemoglobin: 5.5 g/dL, white cell count: 1.42 × 109/L, and platelet count: 19 × 109/L. Liver function showed bilirubin: 47 µmol/L (reference range: 4–23 µmol/L), alanine aminotransferase (ALT): 68 IU/L (7–36 IU/L), alkaline phosphatase (ALP): 1,088 IU/L (32–93 IU/L), and albumin: 24 g/L (39–50 g/L). The lactate dehydrogenase (LDH) was 785 IU/L (107–218 IU/L). The renal function test was normal. Coagulation tests showed prothombin time (PT): 19.1 sec, activated partial thromboplastin time (APTT): 63.2 sec, fibrinogen: 0.29 g/L (1.46–3.38 g/L), and D-dimer: 31.04 mg/L (<0.95 mg/L). The pancytopenia prompted a bone marrow examination. The marrow aspirate showed marked lymphohistiocytic infiltration and frequent hemophagocytosis (Fig. 1A). The constellation of unexplained pyrexia, hepatosplenomegaly, pancytopenia, hypofibrinogenemia, and marrow hemophagocytosis was consistent with the syndrome of hemophagocytic lymphohistiocytosis (HLH). HLH is a hyperinflammatory condition caused by unchecked and dysregulated stimulation of the immune system 1-3. HLH is classified etiologically as primary and secondary (Table 1). Primary HLH pertains to patients who have a history of genetic diseases, and is caused by gene mutations leading to defects in proteins that play important roles in the cytolytic secretory pathway in natural killer (NK) and cytotoxic T-cells (CTL). These defects result in impaired elimination and control of intracellular pathogens, leading to prolonged and enhanced stimulation of the immune system. NK-cells and CTLs secrete large amounts of cytokines that, besides causing a systemic inflammatory response, also activate macrophages, resulting in their infiltration into various organs and hemophagocytosis. Primary HLH manifests in infancy and early childhood, often due to a triggering infectious agent such as Epstein–Barr virus (EBV). Rarely, presentation in adulthood may occur 4. Secondary HLH is a group of heterogeneous disorders, which is reactive to underlying infections, malignancies, and systemic autoimmune diseases. EBV and tuberculosis are common causes of infection-related HLH 2. Lymphomas, predominantly T-cell or NK-cell lymphomas, are the most common underlying malignancies 2. The diagnosis of HLH is based on the HLH-2004 criteria, which stipulate a combination of five or more of the following manifestations: pyrexia; splenomegaly; cytopenia affecting two or more lineages in the peripheral blood; hypertriglyceridemia and/or hypofibrinogenemia; hemophagocytosis in bone marrow, spleen, or lymph nodes; low or absent NK-cell activity; hyperferritinemia, and increased soluble CD25 2. Alternatively, molecular features consistent with HLH can be used to make the diagnosis. The presentation of our patient fulfilled these diagnostic criteria. The advanced age of our patient implied that the HLH was secondary. She was investigated for secondary causes of HLH. Autoimmune serologic markers were normal. A computed tomography (CT) showed gross hepatosplenomegaly with multiple enlarged para-aortic lymph nodes (Fig. 2A). Microbiological and serological tests for infections were negative. The serum ferritin level was markedly elevated to 179,500 pmol/L, which was about 250 times the upper reference limit (reference range: 52–738 pmol/L). Ferritin is an acute phase reactant, and hyperferritinemia is found in various inflammatory and neoplastic conditions. The degree of hyperferritinemia provides diagnostic clues (Table 2). Mild infections, inflammatory conditions, liver diseases and autoimmune disorders rarely result in ferritin of > 5 times normal 5. Ferritin of higher levels might be found in patients with malignancies, particularly lymphoproliferative diseases. Much higher levels of ferritin are found in HLH and lymphomas 1-3. Macrophages are the main source of serum ferritin 6. In HLH, macrophage activation by massive release of cytokines, including interleukin-1 (IL-1), IL-6, and tumor necrosis factor alpha (TNF-α), also leads to secretion of ferritin from macrophages, accounting for the hyperferritinemia. Few conditions result in very high (>50 times) levels of ferritin, and iron overload and severe infections such as disseminated tuberculosis 7 should be considered. For extreme hyperferritinemia (>100 times), juvenile idiopathic arthritis and adult onset Still's disease (AOSD) are virtually the only known causes 8. Extreme hyperferritinemia rendered AOSD a likely diagnosis. A profile of serum cytokines was obtained, showing IL-6 at 3.9 pg/mL (reference value: 5.3 ± 0.4 pg/mL), IL-8 at 22.4 pg/mL (8.3 ± 5.0 pg/mL), and TNF-α at 9 pg/mL (5.6 ± 0.9 pg/mL) 9. Together with the clinical presentation, features were consistent with AOSD. The severe pancytopenia due to hemophagocytosis was compatible with macrophage activation syndrome (MAS) complicating AOSD. AOSD is an idiopathic inflammatory condition. It is diagnosed according to the Yamaguchi's criteria 10. A diagnosis requires fulfilling five or more criteria, which should include at least two major criteria, consisting of fever, arthralgia, typical rash, and leucocytosis; and other minor criteria, consisting of sore throat, lymphadenopathy and/or splenomegaly, liver dysfunction, and the absence of rheumatoid factor and antinuclear antibody. Many subsequent studies have also proposed hyperferritinemia to be included as a diagnostic criterion, as it is found in virtually every case of AOSD 5. Furthermore, AOSD is also marked by increased proinflammatory cytokines, including IL-6, IL-8, and TNF-α 9. In our case, the clinical features, hyperferritinemia, and increased IL-8 and TNF-α were findings consistent with AOSD. When cytopenia occurs in AOSD, MAS has to be considered. MAS is predominantly a pediatric condition, classically associated with juvenile idiopathic arthritis and systemic lupus erythematosus 11. Clinical presentation is similar to HLH. A recent international study listed the following clinical presentations (in descending order of importance): thrombocytopenia, hyperferritinemia, marrow hemophagocytosis, impaired liver function, leucopenia, persistent fever ≥38°C, falling erythrocyte sedimentation rate, hypofibrinogenemia, and hypertriglyceridemia 12. The pathogenesis is also thought to be related to massive release of cytokines due to systemic inflammation. MAS leads to serious organ dysfunction and significantly increases mortality 11, so that its timely diagnosis and treatment is necessary. The liver function progressively worsened, showing bilirubin: 267 µmol/L, ALP: 349 IU/L, and ALT: 82 IU/L. In view of progressive liver failure, a transjugular liver biopsy was performed. It showed cholestasis, and mild microvesicular and macrovesicular steatosis. There was, however, no evidence of massive macrophage infiltration and hemophagocytic activities (Fig. 1B). She was treated with intravenous methyprednisolone at 1 mg/kg, which resulted in rapid improvement in the blood count, coagulation profile, and liver function. Two weeks after treatment, the blood count was almost normalized (hemoglobin: 10.1 g/dL, white cell count: 2.43 × 109 /L, neutrophil: 1.8 × 109 /L, and platelet count: 212 × 109 /L). Liver biopsy in MAS typically shows massive infiltration of portal tract and sinuosids by hemophagocytic CD68-positive macrophages 13. This feature was not found in our case. The absence of hemophagocytic activity in the liver biopsy was also atypical of HLH 1-3. The occurrence of massive hepatomegaly and rapid-onset liver dysfunction due to steatohepatitis was also interesting. Recent studies of non-alcoholic steatohepatitis have shown that TNF-α and to a lesser extent IL-6 are key cytokines that damage the liver, leading to steatosis and inflammation 14. The features in our case might therefore be due to increases in pro-inflammatory cytokines, resulting in the extreme hyperferritinemia and the hepatic steatosis. Therefore, findings in our patient were consistent with a secondary HLH related to hypercytokinemia, implying that further investigations should be pursued to define the primary systemic disease. There are no established treatment guidelines for MAS, which is usually treated similarly to HLH. The mainstay of treatment is high-dose corticosteroids. Dexamethasone and intravenous etoposide are often employed 15. An underlying secondary cause such as lymphomas, other malignancies, infections, and autoimmune diseases should be actively sought for. A positron emission tomography (PET)-CT was performed. It showed hypermetabolic mediastinal and para-aortic lymph nodes, with standard uptake value maximum (SUVmax) of 9.4 and 10.4, respectively (Fig. 2B). As the patient was asymptomatic, and her blood counts and serum biochemistry had almost completely normalized, the lymphadenopathy was initially considered reactive. Prednisolone was tapered off over the next two weeks. Fever recurred, and the platelet count gradually fell to 35 × 109 /L. The cytokine profile was repeated, and showed significant deterioration (IL-6: 29.8 pg/mL; IL-8: 29.8 pg/mL; TNF-α: 18.3 pg/mL). She was re-started on methylprednisolone at 1 mg/kg. The platelet count and fever did not respond to re-institution of corticosteroids. An excisional biopsy of the paratracheal lymph node was performed. It showed the presence of lymphocytic and histiocytic infiltration. Scattered very large atypical lymphoid cells with enlarged, hyperchromatic and vesicular nuclei were identified. Infrequent multinucleated cells were found. Some of them showed prominent nucleoli. Occasional binucleated cells, resembling Reed-Sternberg cells, were also seen (Fig. 3). The atypical lymphoid cells were strongly positive for CD30 and CD15, and weakly positive for PAX5. They were negative for CD20, CD3, CD5, and CD56. In situ hybridization (ISH) for Epstein-Barr virus-encoded small RNAs (EBER) was negative. The histopathologic findings were most consistent with classical Hodgkin lymphoma. HLH has been reported to complicate Hodgkin lymphoma. In 34 cases of Hodgkin lymphoma with HLH, there was a male predominance, a higher frequency of lymphocyte depleted and mixed-cellularity subtypes, and disseminated disease on presentation. Interestingly, EBV infection in the lymphoma cells was found in 94% of cases associated with HLH 16; whereas in most Hodgkin lymphoma, without the presence of HLH, EBV infection is only found in 20–40% of cases. However, EBV infection was not found in our case. A PET-CT was repeated and showed multiple hypermetabolic mediastinal and para-aortic lymph nodes, and diffuse skeletal and bone marrow uptake. Hence, bone marrow examination was repeated. Histiocytic infiltration and prominent hemophagocytosis was observed as before. However, a small number of very large-sized abnormal lymphoid cells with occasional binucleated forms were identified (Fig. 4). The large abnormal cells were positive for CD30 and weakly positive for PAX-5. They were negative for CD20, CD2, CD3, CD5, CD7, and the anaplastic lymphoma kinase protein. Clonal T-cell receptor gene rearrangement could not be found. The overall diagnosis was consistent with Stage IV Hodgkin lymphoma, leading to HLH/MAS. She was treated with escalated BEACOPP (bleomycin, epirubicin, adriamycin, cyclophosphamide, vincritine, prednisolone, and procarbazine). The pyrexia rapidly subsided, and her blood count and liver function normalized about four weeks afterwards. Lymphomas most commonly associated with HLH are of T-cell and NK-cell lineages. Some of the well known conditions include subcutaneous panniculitis-like T-cell lymphoma 17 and extranodal NK/T-cell lymphoma, nasal type 18. HLH secondary to B-cell lymphomas is rare, with intravascular lymphoma an uncommon example 19. This case illustrated the complexity of the diagnosis of HLH, which requires a multidisciplinary approach. There were also a number of interesting observations. The diagnosis of Hodgkin lymphoma is often straight-forward 20 when the disease presents with lymphadenopathy. However, presentations as autoimmune phenomena 21 and other atypical features might render the diagnosis difficult, as illustrated in this case. With the extreme hyperferritinemia (hitherto not been reported before in any histologic subtype of lymphoma) and cytokine profile, the actual diagnosis of Hodgkin lymphoma was elusive, masquerading as AOSD. This case showed that when atypical features are present, every clue should be pursued so that a correct diagnosis may be made. The hepatomegaly and severe liver derangement due to steatohepatitis showed that hepatic failure in HLH might not always be due to macrophage infiltration and hemophagocytosis. An alternative mechanism is severe steatohepatitis induced by hyper-secretion of cytokines. This proposed pathogenesis will need to be further validated.