Panniculitis-like T-cell-lymphoma in the mesentery associated with hemophagocytic syndrome: autopsy case report

A 65-years old previously fit and well Caucasian male patient presented to a small district general hospital with a 3 weeks history of recurrent rigors, fevers and night sweats. He was found to have kidney injury and thrombocytopenia. The whole-body CT (computed tomography) scan revealed in the retroperitoneal space a lesion measuring approx. 13x8x8cm (Fig. 1). The patient was referred to our hospital for further evaluation and treatment. At presentation, blood biochemistry showed low platelets (55 × 10⁹/L, reference range (ref.) 150–400), low white blood cells (3.2 × 10⁹/L, ref. 4.0–10.0) with lymphocytopenia (0.47 × 10⁹/l, ref. 0.8–4.0). The liver enzymes were elevated, too (Alanine Aminotransferase 1.16μkat/l, ref. < 0.73; Aspartate Aminotransferase 3.56μkat/l, ref. < 0.67) and albumin was low (21.9 g/l, ref. 35.0–53.0). The patient underwent explorative laparotomy, which revealed a tumor in mesocolon ascendens invading radix mesenterii. A surgical biopsy was performed. Few days later, he developed progressive pancytopenia, coagulopathy (fibrinogen 0,7 g/l) and his serum C-reactive protein concentration increased (140 mg/l). The patient was readmitted to the intensive care unit and treated with platelet transfusions, fibrinogen, prothrombin complex concentrates and broad-spectrum antibiotics. Despite all these measures, he developed multi-organ failure with dominant liver failure (Aspartate aminotransferase 18.64 μkat/l, ref. < 0.67; Bilirubin 158.4 μmol/l, ref. < 21.0) and refractory shock. He died 22 days after the initial presentation. At the time of death, the underlying disease leading to death was not known. An autopsy was performed.

Two formalin-fixed adipose tissue fragments with the size of 16x8x4 mm and 12x7x3 mm were sent to the Department of Pathology. Microscopically, we saw adult fat tissue with dense lymphocytic infiltration. The lymphocytic infiltration consisted mostly of small- to medium-sized cells with hyperchromatic irregular nuclei with little rim of pale cytoplasm. There was a pattern of isolated adipocytes surrounded by a dense rim of hyperchromatic lymphocytes (Fig. 2). We also found necrotic adipocytes and reactive macrophages phagocytizing lymphocytes and erythrocytes. Immunohistochemically, the atypical cells rimming the adipocytes stained for CD45(LCA), CD2, CD3, CD5, CD7, CD8, granzyme B, perforin, TIA1 and TCRβF1 and did not stain for CD4, CD20, CD79a, CD56, CD30, EBER, CD1a, S100, myeloperoxidase, cytokeratin CAM5.2 and TCRγ. The proliferation index Ki67 varied between 10 and 50% (Fig. 3).

Genomic deoxyribonucleic acid (DNA) from formalin-fixed paraffin-embedded (FFPE) tissue section was isolated using the QIAamp DNA FFPE Tissue Kit (Qiagen GmbH, Hilden, Germany). The clonality of the TCR rearrangements (TCR β, γ and δ) were tested using standardized multiplex polymerase chain reaction (PCR), as described by the BIOMED2 study group [8]. The clonality of the PCR products was assessed using an Agilent 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA, USA), with detection of clonal rearrangement of TCR-γ. Tests for clonal rearrangement in TCR-β and TCR-δ were negative.

Based on these morphological, immunohistochemical and molecular findings, we diagnosed panniculitic T-cell lymphoma with morphological and immunohistochemical features of SPTCL.

During outer inspection we found yellowish color of entire skin and cutaneous suffusions in the abdominal and genital regions. During the inner inspection, there was a thickened, firm, whitish area approx. 12x10x10 cm in the mesocolon ascendens. Intestine and mesenteric lymph nodes were unremarkable. Spleen was enlarged (470 g) and of soft consistency without focal lesions. Liver (2100 g) had a blunt margin, soft consistency and yellow cut surface. Other organs were unremarkable on gross examination. We collected samples for histopathological examination. We specifically and thoroughly examined subcutaneous adipose tissue and looked for any signs of a tumor. We have only found superficial reddish spots that were also sampled for microscopy.

Histopathological examination of mesenterial fat tissue revealed similar findings to those described above in the biopsy: adult fat tissue with atypical hyperchromatic lymphoid cells rimming the adipocytes, with macrophages engulfing whole lymphocytes and erythrocytes (Fig. 4c). In the spleen there was marked activation of red pulp with abundant histiocytes but no signs of infiltration by lymphoma. The bone marrow had cellularity about 50%, with trilinear hematopoiesis, with admixture of macrophages with signs of hemophagocytosis of lymphocytes and red blood cells (Fig. 4a). The immunohistochemistry of the vertebral bone marrow showed focal infiltration of CD8+ lymphocytes rimming the adipocytes; the finding is highly suspect from presence of lymphoma cells in the bone marrow (Fig. 4b). Liver tissue showed marked steatosis with cholestatic features (Fig. 4d), but no signs of lymphoma (Fig. 4e). Histopathological examination of the other organs, including abdominal skin and subcutaneous fat tissue (Fig. 4f), was unremarkable.

The autopsy determined the underlying disease as T-cell lymphoma with cytotoxic phenotype, with morphological and immunohistochemical features of SPTCL, associated with signs of hemophagocytic syndrome (clinical findings of fever, bicytopenia and hypofibrinogenemia, autoptic finding of enlarged liver and spleen and histiocytic hemophagocytosis of lymphocytes and red blood cells), probably leading to patients death due to multiorgan failure, in line with reported clinical features.