Demographics and additional haematologic cancers of patients with histiocytic/dendritic cell neoplasms

AIMS

The discovery of somatic genetic alterations established many histiocytic disorders as haematologic neoplasms. We aimed to investigate the demographic characteristics and additional haematologic cancers of patients diagnosed with histiocytic disorders in The Netherlands.

METHODS AND RESULTS

We retrieved data on histiocytosis patients from the Dutch Nationwide Pathology Databank (Palga). During 1993 to 2022, more than 4000 patients with a pathologist-assigned diagnosis of a histiocytic disorder were registered in Palga. Xanthogranulomas were the most common subtype, challenging the prevailing assumption that Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder. LCH and juvenile xanthogranuloma (JXG) had a peak incidence in the first years of life; males were overrepresented among all histiocytosis subgroups. 118 patients had a histiocytic disorder and an additional haematologic malignancy, including 107 (91%) adults at the time of histiocytosis diagnosis. In 16/118 patients, both entities had been analysed for the same genetic alteration(s). In 11 of these 16 patients, identical genetic alterations had been detected in both haematologic neoplasms. This included two patients with PAX5 p.P80R mutated B cell acute lymphoblastic leukaemia and secondary histiocytic sarcoma, further supporting that PAX5 alterations may predispose (precursor) B cells to differentiate into the myeloid lineage. All 4/11 patients with myeloid neoplasms as their additional haematologic malignancy had shared N/KRAS mutations.

CONCLUSIONS

This population-based study highlights the frequency of xanthogranulomas. Furthermore, our data add to the growing evidence supporting clonal relationships between histiocytic/dendritic cell neoplasms and additional myeloid or lymphoid malignancies. Particularly adult histiocytosis patients should be carefully evaluated for the development of these associated haematologic cancers.

BCR-ABL negative myeloproliferative neoplasia: a review of involved molecular mechanisms

The clonal bone marrow stem cell disorders essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (PMF) belong to the group of Philadelphia chromosome negative myeloproliferative neoplasia (Ph- MPN). In 2005 the JAK2(V617F) mutation was discovered which has generated more insight in the pathogenetic mechanism of the MPNs. More mutations have been detected in MPN patients since. However, the underlying cause of MPN has not been discovered so far. The mechanism of increased angiogenesis in MPNs and the development of fibrosis in the bone marrow in PMF patients and in some ET and PV patients is still not known. This review will focus on the most important molecular pathogenetic mechanisms in MPN patients.

T-cell large granular lymphocytic leukaemia with an uncommon clinical and immunological phenotype

A 39-year-old man presented with a rapidly growing unilateral painless nodule on the right cheek. Histopathological examination and peripheral blood analysis both showed a population of T-cell large granular lymphocytes, which were CD1+, CD2+, CD5+, CD7+ and CD16+, with expression of cutaneous lymphocyte-associated antigen. Further laboratory examination revealed severe neutropaenia, relative lymphocytosis and a clonally rearranged T-cell receptor. The cutaneous manifestation of T-cell large granular lymphocytic leukaemia is very rare. In this particular patient, however, it was instrumental in establishing the diagnosis and may have been enabled by the expression of cutaneous lymphocyte-associated antigen on the cell surface.

Erythema nodosum as an early sign of Crohn's disease

Erythema nodosum is the most common form of septal panniculitis and the most frequent skin manifestation associated with inflammatory bowel disease. Since the development of erythema nodosum is closely related with a variety of disorders and conditions, it can serve as an important early sign of systemic disease. We report on a 25-year-old woman with Crohn's disease following a long history of recurrent erythema nodosum.

Cutaneous granulomas in rheumatoid arthritis

A 57-year-old man with rheumatoid arthritis and myasthenia gravis developed an asymptomatic erythematous plaque on his nose and skin-colored nodules on the elbows. Histopathological examination was suggestive of palisaded neutrophilic granulomatous dermatitis (PNGD). PNGD is a rather uncommon cutaneous finding in different collagen vascular disorders that can manifest with a broad range of clinical symptoms and histological signs. Based on the case report of the patient described here, we briefly discuss what is currently known about this disease.

Protein geranylgeranylation is critical for the regulation of survival and proliferation of lymphoma tumor cells

PURPOSE

Prenylation is essential for membrane localization and participation of proteins in various signaling pathways. The following study was conducted to examine the importance of protein farnesylation and geranylgeranylation for the regulation of lymphoma cell survival and proliferation.

EXPERIMENTAL DESIGN

Lymphoma cells were treated with the beta-hydroxy-beta-methylglutaryl-CoA reductase inhibitor lovastatin, which inhibits protein farnesylation and geranylgeranylation by the depletion of intracellular pools of farnesylpyrophosphate and geranylgeranylpyrophosphate. In addition, farnesyl transferase and geranylgeranyl transferase activities were specifically inhibited by FTI-277 and GGTI-298, respectively.

RESULTS

Only inhibition of geranylgeranylation by lovastatin led to reduction of cell viability in lymphoma cell lines and purified tumor cells from lymphoma patients in a time- and dose-dependent way. Reduction in the number of viable cells was mediated by both induction of apoptosis and inhibition of proliferation. In addition, GGTI-298 was more effective in induction of apoptosis and inhibition of proliferation than FTI-277. Apoptosis induced by inhibition of protein geranylgeranylation was associated with a reduction of Mcl-1 protein levels, collapse of the mitochondrial transmembrane potential, and caspase-3 activation. Inhibition of proliferation resulted from the induction of G(1) arrest. Furthermore, lovastatin at low concentrations sensitized lymphoma cells to dexamethasone, including cells resistant to this drug.

CONCLUSION

These results indicate that protein geranylgeranylation is critical for the regulation of lymphoma tumor cell survival and proliferation and that pharmacological agents such as lovastatin or geranylgeranyl transferase inhibitors, alone or in combination with other drugs, may be useful in the treatment of lymphoma.

Peripheral T-cell lymphomas unspecified presenting in the skin: analysis of prognostic factors in a group of 82 patients

In the present study the clinicopathologic and immunophenotypic features of 82 patients with a CD30- peripheral T-cell lymphoma, unspecified, presenting in the skin were evaluated. The purpose of this study was to find out whether subdivision of these lymphomas on the basis of cell size, phenotype, or presentation with only skin lesions is clinically relevant. The study group included 46 primary cutaneous CD30- large cell lymphomas and 17 small/medium-sized T-cell lymphomas as well as 17 peripheral T-cell lymphomas with both skin and extracutaneous disease at the time of diagnosis. Patients with primary cutaneous small- or medium-sized T-cell lymphomas had a significantly better prognosis (5-year-overall survival, 45%) than patients with primary cutaneous CD30- large T-cell lymphomas (12%) and patients presenting with concurrent extracutaneous disease (12%). The favorable prognosis in this group with primary cutaneous small- or medium-sized T-cell lymphomas was particularly found in patients presenting with localized skin lesions expressing a CD3+CD4+CD8- phenotype. In the primary cutaneous T-cell lymphoma (CTCL) group and in the concurrent group, neither extent of skin lesions nor phenotype had any effect on survival. Our results indicate that peripheral T-cell lymphomas, unspecified, presenting in the skin have an unfavorable prognosis, irrespective of the presence or absence of extracutaneous disease at the time of diagnosis, cell size, and expression of a CD4+ or CD8+ phenotype. The only exception was a group of primary cutaneous small- or medium-sized pleomorphic CTCLs with a CD3+CD4+CD8- phenotype and presenting with localized skin lesions.