
The final diagnosis of LCH combined with secondary HLH was made according to HLH-2004 criteria (not meeting molecular biology diagnostic criteria but meeting at least five of the eight clinical and laboratory indicators), after excluding leukemia and lymphoma. There were no gene mutations seen in the genetic testing associated with hemophagocytic lymphohistiocytosis (HLH). Epstein-Barr virus and cytomegalovirus DNA tests were negative. Subsequently, bone marrow puncture clearly revealed hemophagocytosis. Based on these findings, he was considered for a diagnosis of Langerhans cell histiocytosis (LCH) with a multisite type. He was first considered for lymphoma, but biopsies of bilateral axillary lymph nodes revealed diffuse hyperplasia of Langerhans histiocytes, and immunohistochemistry showed S100 (++) and CD1a (++). Cranial and extremity bone radiographs indicated osteoporosis with no abnormal bone destruction. Contrast-enhanced CT of the abdomen revealed multiple enlarged lymph nodes in the hepatogastric space and retroperitoneum. NK cell activity was reduced or even non-existent. The second laboratory test showed a white blood cell count of 0.34 × 10 9/l (normal range: 4–10), neutrophil count of 0.01 × 10 9/l (normal range: 2–7), neutrophil percentage of 10.7% (normal range: 50–70), hemoglobin of 96 g/l (normal range: 110–150), platelets of 35 × 10 9/l (normal range: 100–300), high-sensitivity C-reactive protein greater than 10 mg/l, fibrinogen of 1.44 g/l (normal range: 2–4), D-dimer level of 1.68 µg/ml (normal range: 0–0.5), lactate dehydrogenase of 311 IU/l, serum ferritin level of 599.7 ng/ml (normal range: 15–200) and triglycerides of 3.1 mmol/l (normal range: 0–1.7). Over the next 1 week, he developed recurrent hyperthermia without any infectious conditions, with fever peaking over 38.5☌. He was subsequently given dexamethasone and cimetidine to treat the rash. Routine blood tests on the first day of admission were normal, with only the lactate dehydrogenase elevated to 498 IU/l (normal range: 120–250). On examination, he had no fever and presented with a generalized scattered patchy red rash with pruritus, and several enlarged lymph nodes that were hard, nontender, movable, and approximately 5 mm in diameter could be palpated in the bilateral axillae. He had a previous history of gallbladder stones and had no episodes of biliary colic no significant family history was present. A 73-year-old man was referred to our hospital with intermittent diarrhea and a generalized scattered red rash for 5 days.
