A rare case of hepatosplenic gamma-delta T-cell lymphoma and secondary hemophagocytic lymphohistiocytosis

Capillaritis as a Skin Manifestation of Hepatosplenic Gamma-Delta T-Cell Lymphoma

We present the case of a 10-year-old boy who was admitted with 3 months of episodic febrile neutropenia and a new petechial rash. Routine bloods identified neutropenia, thrombocytopenia, and a raised alanine aminotransferase. The dermatology team was consulted in light of the symmetrical petechial eruption of the upper torso. A punch biopsy of the lesion was consistent with early capillaritis. The results showed superficial dermal red blood cell extravasation with mild perivascular lymphohistiocytic inflammatory infiltrate. There was no evidence of an atypical lymphoid infiltrate in the skin biopsy. An initial bone marrow aspirate showed an abnormal mature T-cell population consisting of CD4 and CD8 T cells with gamma-delta positivity. Karyotyping was also done, which demonstrated isochromosome 7q. These findings were consistent with a diagnosis of hepatosplenic T-cell lymphoma (HSTL). The patient underwent fourth-line chemotherapy due to refractory relapsing disease but sadly passed away within 12 months of diagnosis. HSTL is a rare and aggressive subset of peripheral T-cell lymphoma. Prognosis is poor with a median survival of <1 year from diagnosis. However, reports suggest improved outcomes if intensive, early, high-dose chemotherapy is used alongside hematopoietic stem cell transplantation. Therefore, there is an impetus to attain early diagnosis for aggressive early treatment and improved patient outcomes. Capillaritis, presenting as asymptomatic nonpalpable purpura, can be a rare presenting feature of HSTL. Dermatologists could play a pivotal role in the early recognition of this rare but aggressive hematological malignancy and promote prompt treatment resulting in better patient outcomes.

Pathology updates and diagnostic approaches to hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a complex, often under-recognized hyperinflammatory immune dysregulation syndrome arising in a diverse range of clinical scenarios and conditions. The accurate and timely diagnosis of HLH is crucial for patient survival, and usually requires a high level of clinical suspicion. The histologic corollary to clinical HLH - hemophagocytosis - is neither necessary nor sufficient for the diagnosis of HLH, as it may be seen in a variety of reactive conditions and may be absent in true HLH. Nevertheless, the finding of hemophagocytosis in specific clinical situations should prompt consideration of HLH and further testing to exclude the condition. While traditionally described in bone marrow, identification of hemophagocytosis in other tissues, including lymphoid, splenic, liver, or neural tissue, can be an important asset to the overall recognition of HLH. In this review we discuss the underlying pathophysiology and etiologies of HLH, morphologic aspects of hemophagocytosis and its associated histologic findings in different tissues, and give a brief overview of diagnostic criteria and clinical evaluation.