Cutaneous involvement in chronic myelomonocytic leukemia

Leukemia Cutis Presenting as a Morbilliform Eruption: A Case Report and Literature Review

Leukemia cutis (LC) is a broad term that describes the infiltration of neoplastic leukocytes into the skin. Classically, LC is characterized by erythematous papules and nodules. However, LC can have a widely variable presentation. Therefore, it is crucial to maintain a high index of suspicion for LC through a complete clinical assessment, histopathology, and immunohistochemistry to distinguish this entity from other clinical mimickers. Herein, we report a case of biopsy-proven LC presenting as a morbilliform eruption that was initially suspected to be a drug eruption in a child with acute monocytic leukemia.

Leukaemia cutis as a specific skin involvement in chronic myelomonocytic leukaemia and review of the literature: Acknowledgments

The skin involvement of myeloid leukaemia is conventionally divided into specific malignant lesions and non-specific benign lesions, and these categories are also applicable in chronic myelomonocytic leukaemia (CMML). According to the 2016 World Health Organization (WHO) classification of tumours of haematopoietic and lymphoid tissues, CMML is defined as a myeloid neoplasm with characteristics of myelodysplastic syndrome (MDS) and myeloproliferative neoplasms (MPNs). As a specific cutaneous sign of extramedullary infiltration, leukaemia cutis (LC) is a rare occurrence in patients with CMML, and only approximately 89 cases have been reported in the literature thus far. The clinical features of LC are varied, and LC in CMML exhibits heterogeneous histopathologic features, with manifestations as cutaneous nodules or papules that are composed of blast cells showing either granulocytic or monocytic differentiation. Skin biopsy and further immunohistochemical examination are essential at the time of diagnosis to evaluate pathological type and determine the clinical course. Generally, once diagnosed as LC in CMML, this unusual skin lesion might be an indicator of transformation to acute myeloid leukaemia (AML) and is associated with a poor prognosis. The main treatment is allogeneic stem cell transplantation (ASCT). Therefore, early diagnosis and accurate identification have important therapeutic and prognostic significance in CMML patients with skin infiltration.

How I treat chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic malignancy that may deserve specific management. Defined by a persistent peripheral blood monocytosis ≥1 × 10⁹/L and monocytes accounting for ≥10% of the white blood cells, this aging-associated disease combines cell proliferation as a consequence of myeloid progenitor hypersensitivity to granulocyte-macrophage colony-stimulating factor with myeloid cell dysplasia and ineffective hematopoiesis. The only curative option for CMML remains allogeneic stem cell transplantation. When transplantation is excluded, CMML is stratified into myelodysplastic (white blood cell count <13 × 10⁹/L) and proliferative (white blood cell count ≥13 × 10⁹/L) CMML. In the absence of poor prognostic factors, the management of myelodysplastic CMML is largely inspired from myelodysplastic syndromes, relying on erythropoiesis-stimulating agents to cope with anemia, and careful monitoring and supportive care, whereas the management of proliferative CMML usually relies on cytoreductive agents such as hydroxyurea, although ongoing studies will help delineate the role of hypomethylating agents in this patient population. In the presence of excessive blasts and other poor prognostic factors, hypomethylating agents are the preferred option, even though their impact on leukemic transformation and survival has not been proved. The therapeutic choice is illustrated by 4 clinical situations among the most commonly seen. Although current therapeutic options can improve patient's quality of life, they barely modify disease evolution. Improved understanding of CMML pathophysiology will hopefully lead to the exploration of novel targets that potentially would be curative.

Specific skin lesions in chronic myelomonocytic leukemia: a spectrum of myelomonocytic and dendritic cell proliferations: a study of 42 cases

Chronic myelomonocytic leukemia (CMML) is a rare clonal hematopoietic disorder that can also involve the skin. The histopathology of these skin lesions is not clearly defined, and few data are available in the literature. To better understand tumoral skin involvements in CMML we carried out an extensive, retrospective clinicopathologic study of 42 cases selected from the database of the French Study Group of Cutaneous Lymphomas. On the basis of clinical data, morphology, and phenotype we identified 4 clinicopathologic profiles representing 4 distinct groups. The first group comprised myelomonocytic cell tumors (n=18), exhibiting a proliferation of granulocytic or monocytic blast cells, which were CD68 and/or MPO positive but negative for dendritic cell markers. The second group comprised mature plasmacytoid dendritic cell tumors (n=16), denoted by a proliferation of mature plasmacytoid dendritic cells, which were CD123, TCL1, and CD303 positive but CD56, CD1a, and S100 negative. The third group comprised blastic plasmacytoid dendritic cell tumors (n=4), characterized by a proliferation of monomorphous medium-sized blast cells, which were CD4, CD56, CD123, TCL1 positive but CD1a and S100 negative. The fourth group consisted of a putatively novel category of tumor that we named blastic indeterminate dendritic cell tumors (n=4), distinguished by a proliferation of large blast cells that not only exhibited monocytic markers but also the dendritic markers CD1a and S100. These 4 groups showed distinctive outcomes. Finally, we showed, by fluorescence in situ hybridization analysis, a clonal link between bone marrow disease and skin lesions in 4 patients. Herein, we have described a novel scheme for pathologists and physicians to handle specific lesions in CMML, which correspond to a spectrum of myelomonocytic and dendritic cell proliferations with different outcomes. A minimal panel of immunohistochemical markers including CD68, CD1a, S100, Langerin, and CD123 is necessary to make the correct classification in this spectrum of cutaneous CMML tumors, in which dendritic cell lineage plays an important role.

Cutaneous leukaemic infiltrations in a patient with previously undiagnosed myelodysplastic syndrome

We report the rare case of a patient with leukaemia cutis first presenting only on the hand and fingers and then subsequently spreading over the trunk and face. The lesions heralded the transformation of a previously undiagnosed myelodysplastic syndrome type RAEB (refractory anaemia with blast excess) into frank myeloid leukaemia. The haematological disease was first detected by the dermatohistopathologist. This case underlines the need to look meticulously for skin changes and perform early skin biopsies in haematological patients, as the skin can reveal the first clinical signs of an otherwise not evident bone marrow disorder. Leukaemia cutis as the initial clinical presentation of a transforming myelodysplastic syndrome type RAEB into acute myeloid leukaemia has been reported only very rarely.

Skin involvement in chronic myelomonocytic leukaemia as a predictor of transformation into acute myeloid leukaemia

We report on the case of a patient with myelodysplastic syndrome (MDS) who presented with leukaemia cutis preceding development of acute myeloid leukaemia. Leukaemic infiltration of the skin should be considered an early manifestation of leukaemic transformation and an indicator of poor prognosis in MDS.

Monocytic leukemia cutis diagnosed simultaneously with refractory anemia with monocytosis: a case report

A case of leukemia cutis (LC) of monocytic lineage in a patient with myelodysplastic syndrome (MDS) is presented. Cutaneous infiltrates were recognized concurrent with diagnosis of refractory anemia (RA) with monocytosis. Skin infiltrates subsequently spontaneously regressed although MDS progressed with increasing monocytosis, anemia, and thrombocytopenia. Death occurred 6 months after diagnosis with evolution of acute monoblastic leukemia complicated by sepsis. This case supports previous observations of poor prognosis associated with leukemia cutis. LC associated with MDS is reviewed including the role of monocytes.

Histopathologic aspects of cutaneous metastatic disease

In cutaneous metastatic disease the histologic pattern may be specific or nonspecific. Carcinoma cutis most often shows only the nonspecific pattern of an adenocarcinoma, a squamous cell carcinoma, or an undifferentiated metastatic tumor. However, certain clinical and histologic characteristics may suggest a primary tumor site and type. In addition, special histologic stains and the use of immunohistochemical and electronmicroscopic techniques may also prove valuable in the diagnosis of carcinoma cutis and other cutaneous metastatic diseases.

Cutaneous metastatic disease

The relative frequencies of cutaneous metastases are similar to those of the primary cancers; breast, colon, and melanoma are the most frequent in women and lung, colon, and melanoma are the most common in men. Cutaneous metastases represent an opportunity to detect a potentially treatable cancer before other evidence of it is present, to modify therapy as appropriate to the tumor stage, or possibly to use the cutaneous lesion as a source of easily accessible tumor cells for specific therapy. Cutaneous metastatic disease as the first sign of internal cancer is most commonly seen with cancer of the lung, kidney, and ovary.