Cytophagic histiocytic panniculitis, hemophagocytic lymphohistiocytosis and undetermined autoimmune disorder: reconciling the puzzle

Familial Hemophagocytic Lymphohistiocytosis Screening in Neonatal Sepsis

OBJECTIVE

Neonatal sepsis and familial hemophagocytic lymphohistiocytosis (fHLH) have similar clinical and laboratory symptoms and the possibility of overlooking fHLH diagnosis is high in newborns with sepsis. History of consanguineous marriage and/or sibling death, hepatomegaly/splenomegaly, and hyperferritinemia (>500 ng/mL) are likely to support fHLH in newborns with sepsis. Therefore, in newborns with sepsis in whom at least 2 of these 3 criteria were detected, genetic variants was investigated for the definitive diagnosed of fHLH. According to the results of genetic examination, we investigated whether these criteria supporting fHLH could be used as a screening test in fHLH.

MATERIALS AND METHODS

fHLH-associated genetic variants were investigated in 22 patients diagnosed with neonatal sepsis who fulfilled at least 2 of the following criteria (1) history of consanguineous marriage and/or sibling death, (2) hepatomegaly/splenomegaly, and (3) hyperferritinemia (>500 ng/mL).

RESULTS

Heterozygous variants were determined in 6 patients (27.2%): 3 STXBP2 , 1 STX11 , 1 UNC13D , and 1 PRF1 . Polymorphisms associated with the clinical symptoms and signs of HLH were determined in 5 patients (22.7%): 4 UNC13D , 1 PRF1 . Two patients were in the heterozygous variants and polymorphism associated with the clinical symptoms and signs of HLH groups. In 12 patients, benign polymorphisms were detected in STXBP2 and UNC13D genes. No change in fHLH associated genes were found in 1 patient.

CONCLUSION

Some variants and/or polymorphisms identified in our patients have been previously reported in patients with HLH. Therefore, we recommend further investigation of fHLH in patients with neonatal sepsis who fulfill at least 2 of the above 3 criteria.

Clinicopathological Characteristics and Outcome of Cytophagic Histiocytic Panniculitis: A Single-Center, Retrospective Study

Background

Cytophagic histiocytic panniculitis (CHP) is a rare panniculitis associated with systemic features characterized by the infiltration of subcutaneous adipose tissue by benign-appearing T lymphocytes and phagocytic histiocytes, mimicking hemophagocytic lymphohistiocytosis (HLH) and subcutaneous panniculitis-like T-cell lymphoma (SPTCL).

Purpose

To establish the clinicopathological features and response to treatment of CHP and evaluate the prognosis of patients and guide therapy based on the current state of knowledge.

Material and Methods

Clinical, laboratory, histopathological, and outcome data of 12 patients with CHP were retrospectively collected between 2009 and 2022.

Results

All the patients presented with plaques or nodules, mostly located in the lower extremities (11/12). Fewer cases involved systemic symptoms (9/12) and laboratory abnormalities (6/12), and none were positive for serum Epstein-Barr virus (EBV)-DNA. Histopathological examination revealed mixed septal and lobular inflammatory infiltration of histiocytes and lymphocytes. Large or atypical lymphocytes were rarely present (2/12). In some patients, varying proportions of plasma cells, neutrophils, and eosinophils were observed. The extent of histocytophagy was mild (9/12), moderate (2/12), and severe (1/12). HLH was not observed in any of our cases, none of which were fatal.

Conclusion

The uniqueness of our study lies in the presence of neutrophil-rich dermal and subcutaneous infiltrates, associated with connective tissue disorders (CTD) and streptococcal infections. Our study reveals that EBV-negative CHP tends to a better prognosis than previously research, filling the gap in the much-needed details of CHP in the Chinese population. Moreover, CHP may present as a reactive process in combined primary diseases; further studies are required to validate these findings.

Panniculitis: A Cardinal Sign of Autoinflammation

Panniculitis was first described in the nineteenth century and is characterized by inflammation of the subcutaneous fat. It may be categorized in septal or lobular subtypes, but other histopathological features (e.g., presence of vasculitis, nature of inflammatory infiltrates, characteristics of fat necrosis) are also important for diagnostic purposes. Clinically, panniculitis is characterized by the presence of subcutaneous nodules, and both ulcerative and nonulcerative clinical subtypes have been proposed. In this review, we aimed to describe the occurrence of panniculitis in autoinflammatory disorders (AIDs) and related diseases. Among monogenic AIDs, panniculitis is common in IFN-mediated disorders. Panniculitis is a distinctive feature in proteasome-associated autoinflammatory syndromes (PRAAS), including chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome and Nakajo-Nishimura syndrome. On the other hand, erythema nodosum corresponds to the most common clinical form of panniculitis and is common in polygenic AIDs, such as Behçet's syndrome, inflammatory bowel disease, and sarcoidosis. Cytophagic histiocytic panniculitis, lipoatrophic panniculitis of children, and otulipenia are rare disorders that may also present with inflammation of the subcutaneous fat. Therefore, panniculitis can identify a specific subgroup of patients with AIDs and may potentially be regarded as a cardinal sign of autoinflammation.

Cytophagic Histiocytic Panniculitis Presenting as Subcutaneous Nodules and Generalized Edema - A Case Report

Background

Cytophagic histiocytic panniculitis (CHP) is a rare form of nodular panniculitis characterized by clinical manifestations such as skin erythema, nodules, fever, pancytopenia, liver failure, plasmacytosis, and hepatosplenomegaly. We report a case of CHP that was initially misdiagnosed as subcutaneous panniculitis-like T-cell lymphoma (SPTCL) but achieved complete remission with a favorable prognosis.

Methods

A 38-year-old female presented to the dermatology department with a 15-day history of subcutaneous nodules, generalized edema, and continuous fever.

Results

The patient was diagnosed as CHP combined with hemophagocytic syndrome by typical clinical manifestations, low value of SUVmax in positron emission tomography/computed tomography (PET/CT), benign differentiated T cells, negative TCR gene rearrangement, pancytopenia, abnormal coagulation, hypertriglyceridemia, decreased NK cell count, impaired liver function, and the presence of hemophagocytic cells observed in bone biopsy smears.

Conclusion

In our case, the patient presented with hemophagocytic syndrome with hemodynamic instability, indicating an intensive treatment is needed. The diagnosis of SPTCL necessitates a meticulous process of differential diagnosis, along with the cautious administration of an aggressive chemotherapy regimen. Extended follow-up is imperative to ascertain the long-term outcomes.

Adult-Onset Familial Hemophagocytic Lymphohistiocytosis Presenting with Annular Erythema following COVID-19 Vaccination

Familial hemophagocytic lymphohistiocytosis (HLH) is a rare genetic and life-threatening immunodeficiency disease. Here, we present a 38-year-old male who initially developed multiple annular to irregular erythema accompanied by a fever after COVID-19 vaccination. He was diagnosed with HLH with evidence of leukocytopenia in a full blood test, elevations of ferritin and sCD25, decreased NK cell function, and hemophagocytosis of a bone marrow biopsy specimen. A genetic examination revealed two probable disease-causing heterozygous mutations on UNC13D associated with type 3 familial HLH. A review of the case reports relevant to HLH following COVID-19 vaccination and the cutaneous manifestations of HLH with genetic defects suggests the necessity that individuals with preexisting immune dysregulation or diseases not classified should be cautious about COVID-19 vaccination and reminds clinicians that various recalcitrant skin lesions may be a sign of HLH.

Cytophagic Histiocytic Panniculitis (CHP) in a Patient with SLE Found after Autopsy: When a Rash Is "Complicated!"

Introduction

Cytophagic histolytic panniculitis (CHP) is a clinical disorder characterized by nodular panniculitis of the subcutaneous adipose tissue. It was first described in 1980 by Winkelmann. Histologically it is described as an infiltration of the adipose tissue by T- lymphocytes and phagocytic macrophages (also known as “bean bag cells”). Most of the cases are reported under the age of 50 and is a rare cause of panniculitis. We report a case of CHP in a young patient who presented to our emergency room (ER).

Case Summary

A 39-year-old African American woman who presented to our hospital with lethargy, progressive confusion, and generalized rash involving both lower extremities of 1 week duration. She had a history of pancytopenia and focal proliferative and membranous lupus nephritis classes 3 and 5. Her physical examination was remarkable for bilateral lower extremity pitting edema and a desquamating rash on both of her legs. The Nicolsky sign was positive. She was noted to be hypotensive and was started on intravenous fluids and broad spectrum antibiotics. Routine laboratory tests revealed severe pancytopenia, with a hemoglobin of 3.9 g/dl, white blood cell count 600/ul, and platelet count of 11000/ul. Within an hour of arrival to the ER she developed acute respiratory failure. She was intubated and placed on mechanical ventilation. She developed shock requiring vasopressors. No imaging could be done due to her unstable condition. Four hours after her initial presentation she developed asystole and expired. Postmortem histopathology of the adipose tissue revealed CHP.

Conclusion

CHP can be rapidly fatal. The treatment involves high dose of intravenous steroids and immunosuppressants such as cyclosporine.

Lipophagic Panniculitis of Childhood: A Case Report and Comprehensive Review of the Literature

Lipophagic panniculitis of childhood is a rare condition notable clinically for an inflammatory panniculitis followed by the development of permanent lipoatrophy. In this regard, the term lipoatrophic panniculitis has been used synonymously with lipophagic panniculitis. Additional designations include lipophagic lipoatrophic panniculitis and annular lipoatrophic panniculitis of the ankles. Although lipophagic panniculitis has been associated with a number of autoimmune phenomena, a paucity of reports and limited pathological analyses to date renders this disease an elusive one whose pathogenesis is not yet established. We describe the clinical, histopathologic, and immunohistochemical findings in a case of lipophagic panniculitis of childhood in a 7-year-old boy and present it in the context of a comprehensive review of the literature. Furthermore, we offer a hypothesis regarding the pathogenetic basis of lipophagic panniculitis of childhood, suggesting cellular immunity targeting the adipocyte at the crux of its pathogenesis.

Hereditary and acquired hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare but life-threatening hyperinflammatory/hypercytokinemia syndrome clinicopathologically manifested by fever, hepatosplenomegaly, cytopenias, liver dysfunction, and hemophagocytosis.

METHODS

We searched the medical literature for English-written articles and analyzed data regarding the diagnosis, pathoetiology, prognosis, and management of HLH.

RESULTS

HLH can be subcategorized into primary/genetic (PHLH) or secondary/acquired (SHLH) according to etiology. PHLH, including familial HLH and inherited immune deficiency syndromes, typically occurs in children harboring underlying genetic defects, whereas SHLH frequently manifests in adults and is associated with infection, autoimmunity, immune suppression, or malignancy. The pathogenesis of HLH is still elusive. Its known mechanisms include somatic mutations in gene coding for proteins implicated in the cytotoxic pathways of cytotoxic T or natural killer cells. The impaired ability of these cells to kill target cells leads to an uncontrolled hypercytokinemia and hyperinflammatory process, triggering hemophagocytosis and multiorgan failure. Corticosteroids, chemotherapy, and immunotherapy are the mainstay therapeutic strategies. The consolidation with allogeneic hematopoietic stem cell transplantation is a potentially curative option for PHLH and refractory or relapsed SHLH.

CONCLUSIONS

Understanding of the pathophysiology of HLH has improved in the last decade. The establishment of diagnostic and treatment guidelines for PHLH and SHLH has resulted in earlier diagnoses and the rapid initiation of therapy, both of which are associated with favorable outcomes.

Familial hemophagocytic lymphohistiocytosis: when rare diseases shed light on immune system functioning

The human immune system depends on the activity of cytotoxic T lymphocytes (CTL), natural killer (NK) cells, and NKT cells in order to fight off a viral infection. Understanding the molecular mechanisms during this process and the role of individual proteins was greatly improved by the study of familial hemophagocytic lymphohistiocytosis (FHL). Since 1999, genetic sequencing is the gold standard to classify patients into different subgroups of FHL. The diagnosis, once based on a clinical constellation of abnormalities, is now strongly supported by the results of a functional flow-cytometry screening, which directs the genetic study. A few additional congenital immune deficiencies can also cause a resembling or even identical clinical picture to FHL. As in many other rare human disorders, the collection and analysis of a relatively large number of cases in registries is crucial to draw a complete picture of the disease. The conduction of prospective therapeutic trials allows investigators to increase the awareness of the disease and to speed up the diagnostic process, but also provides important functional and genetic confirmations. Children with confirmed diagnosis may undergo hematopoietic stem cell transplantation, which is the only cure known to date. Moreover, detailed characterization of these rare patients helped to understand the function of individual proteins within the exocytic machinery of CTL, NK, and NKT cells. Moreover, identification of these genotypes also provides valuable information on variant phenotypes, other than FHL, associated with biallelic and monoallelic mutations in the FHL-related genes. In this review, we describe how detailed characterization of patients with genetic hemophagocytic lymphohistiocytosis has resulted in improvement in knowledge regarding contribution of individual proteins to the functional machinery of cytotoxic T- and NK-cells. The review also details how identification of these genotypes has provided valuable information on variant phenotypes.