Hemophagocytic lymphohistiocytosis (HLH) is a syndrome that results in organ infiltration by activated cytotoxic T cells and histiocytes as a result of an excessive inflammatory response and cytokine storm. Patients with HLH exhibit abnormally high levels of TNF-alpha, interleukins (IL) 4, 6, 8, 10, and 12, and soluble IL-2 receptor (sCD25), in addition to abnormally low or nonexistent NK cell activity.[1-3]. The aforementioned factors can help identify this condition from aetiologies that have similar symptoms.

Hemophagocytic lymphohistiocytosis (HLH) is a severe, potentially fatal immune activation condition. HLH is a sporadic or familial condition that can be brought on by several things that disturb immunological homeostasis [4]. This is a rare case report highlighting the diagnosis and treatment plan of a 60-year-old female patient with residual follicular lymphoma with hemophagocytic lymphohistiocytosis.

A 60-year-old female patient presented with complaints of intermittent cough for 10 days accompanied by generalised lymphadenopathy. The patient also gave a history of COVID-19-positive status a year ago. The patient was diagnosed with stage IV NHL Follicular Grade I Lymphoma by USG-guided lymph node biopsy 2 years back. The patient was given 6 cycles of chemotherapy. The patient was also a known case of pulmonary tuberculosis for which she was on ATT for one year.

A year later, on follow-up examination, the patient was found to have multiple enlarged lymph nodes in the cervical region (anterior triangle), left axilla and inguinal region. PET-CT scan showed multiple enlarged lymph nodes in cervical, inguinal and retroperitoneal regions. Laboratory investigations included hemoglobin 8.3g/dl, platelet count 8000 cells/cumm, total WBC count 8800 cells/cumm, differential count neutrophil 01%, lymphocytes 54%, lymphoblasts 45%, triglycerides 578 mg/dl, total cholesterol 375 mg/dl, ferritin 20,250 ng/ml, LDH 11,780 U/L, SGOT 606 U/L, SGPT 147 U/L, Alkaline phosphatase 2126 U/L and Fibrinogen 150 mg/dl.Peripheral smear showed many atypical lymphoid cells with a high N: C ratio, and clumped chromatin. Some showed a cleft nucleus and a single prominent nucleolus.

As a result of an excessive inflammatory response and cytokine insufficiency, hemophagocytic lymphohistiocytosis (HLH) is a disease that causes organ infiltration by activated cytotoxic T cells and histiocytes.[1,2] In a similar rare report by Devitt et al., HLH was connected to adult-onset Still's illness and an underlying autoimmune condition with T-cell/histiocyte-rich large B cell lymphoma.[5] According to a retrospective study by Shabbir et al, adult patients with HLH-associated malignancies had a poor prognosis with a 67% death rate.[6]

Among the clinical symptoms are persistent fever, hepatosplenomegaly, lymphadenopathy, pancytopenia, rash, and neurological problems.[7] Typical laboratory findings in our patient included high triglycerides, notably raised ferritin levels, hypofibrinogenemia, and abnormal liver function tests.

Due to its rarity, cryptic presentation, and abnormal test results, HLH is a difficult diagnosis. Given the importance of early treatment to provide the best outcome, prompt recognition and diagnosis are crucial. The fundamental objective of treatment, particularly when HLH is linked to malignancies, is to target the underlying issue while making an effort to manage the heightened inflammatory response.