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Near early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a rare hematologic malignancy, for which second line therapeutic options are limited. T-cell leukemias are also rarely associated with leukemia cutis, which is more often seen in leukemias of myeloid origin. We present the case of an adult male diagnosed with near ETP-ALL, with IDH2 and DNMT3A mutations, suggestive of a myeloid origin, and leukemia cutis. After the patient progressed on hyper-CVAD and nelarabine, we treated him with the BCL-2 inhibitor venetoclax and the hypomethylating agent decitabine. The regimen induced a rapid bone marrow response and resolution of the leukemia cutis.

Introduction: Acute lymphoblastic leukemia (ALL) is the most common oncological disease in the pediatric population; however, skin infiltration occurs only in 1-3% of the patients and almost always manifests after the diagnosis is made. Clinical case: A male teenage patient who presented with facial edema and infiltration, associated with systemic symptoms such as asthenia and adynamia. On physical examination, the patient presented facial edema and indurated plaques, as well as cervical, inguinal, and axillary adenopathy. Complete blood count showed pancytopenia and a chest X-ray revealed a mediastinal mass. Due to a high suspicion of malignancy a bone marrow and skin biopsy was taken, both with pre-B ALL. Chemotherapy was started and the patient is now in maintenance phase. Conclusions: Leukemia cutis manifestations are heterogenous, from a small papule to a big nodule. It is more common in patients with acute myeloid leukemia and it is rare in patients with pre-B ALL, specially in the pediatric population. The diagnosis should be done with a biopsy and the treatment is with systemic chemotherapy. The diagnosis should always be considered in patients with unexplained edematous or indurated lesions, especially in the context of systemic symptoms. [ABSTRACT FROM AUTHOR]

Simple Summary: Diagnosis of hairy cell leukemia is based on the presence of hairy cells in bone marrow and peripheral blood as well as the characteristic immunophenotype. Moreover, in classic HCL, most patients present with a BRAF V600E mutation. The typical symptoms of classic hairy cell leukemia include pancytopenia, massive splenomegaly and increased risk of infection. However, rarer manifestations of HCL are occasionally reported, including cutaneous symptoms, bone infiltration, arthritis and central nervous system symptoms, as well as gastrointestinal tracts, heart, lungs, ocular involvement and other symptoms. Background: Hairy cell leukemia (HCL) is a rare indolent B-cell lymphoid malignancy. The majority of patients are asymptomatic and HCL is usually diagnosed incidentally during a routine blood cell count. In symptomatic patients, typical symptoms are related to pancytopenia and splenomegaly. In this review, we present rare clinical symptoms in patients with HCL. Methods: A literature search was conducted of PubMed, Web of Science and Google Scholar for articles concerning hairy cell leukemia, leukemia cutis, bone lesions, neurological manifestations, pulmonary symptoms, ocular manifestations, cardiac manifestation and rare symptoms. Publications from January 1980 to August 2024 were scrutinized. Additional relevant publications were obtained by reviewing the references from the chosen articles. Results: Extramedullary and extranodal manifestations of classic HCL are rare. However, leukemic involvement in the skin, bone, central nervous system, gastrointestinal tract, heart, kidney, liver, lung, ocular system and other organs have been reported. [ABSTRACT FROM AUTHOR]

We report a rare manifestation of cutaneous borreliosis in a patient with pre-existing malignant lymphoproliferative disease, in particular chronic lymphocytic B cell leukemia (B-CLL). The patient’s cutaneous lesions were initially diagnosed histologically as leukemia cutis. Distribution pattern of the skin lesions were in typical localizations for borrelial lymphocytoma. Borrelia burgdorferi sensu stricto was isolated and cultured from two sites (ear, mammilla). Antibiotic therapy improved the cutaneous lesions and the general condition of the patient. However, a second round of antibiotic therapy was required to resolve the lesions. At eleven years of follow-up the patient’s skin was clear and she still had a stable condition of B-CLL without chemotherapy. In conclusion, the patient suffered from Lyme borreliosis (Borrelia lymphocytoma) and the cutaneous symptoms were aggravated by the underlying condition of chronic B-CLL condition.

Key Clinical Message: Clinical presentation of leukemia cutis (LC) is polymorphic and can reveal a malignant hemopathy. More commonly described in cases of acute myeloid leukemia (AML), LC can also occur in case of chronic myeloid leukemia (CML). Leukemia cutis is a rare form of extramedullary feature of malignant hemopathy, seldom associated with CML. Its clinical presentation is pleiotropic and differential diagnosis is broad. It relies on clinical and typical histological and biomolecular concordance. Once confirmed, treatment is based on that of the primary condition. We present a case of a leukemia cutis revealing a relapse of a CML successfully treated by tyrosine kinase inhibitor. [ABSTRACT FROM AUTHOR]

Abstract A newborn girl had typical “blueberry muffin” skin lesions, which shows histopathologic features of monocytic leukemia cutis. The systemic leukemia was demonstrated after one month of life. She was treated by chemotherapy, including induction and three consolidation cures, according to the ELAM02 protocol, which led to complete remission. This case report with congenital form of AML5 cutaneous localization, preceding systemic involvement, with a 5‐year follow‐up and positive outcome is remarkable.

Leukemia cutis is a term used to describe cutaneous manifestations of leukemic infiltration of the skin and portends a poor prognosis. Cutaneous involvement by hematopoietic/lymphoid tumors can occur before, concurrently, or after the initial diagnosis. Early involvement of dermatologists and timely biopsies play a crucial role in achieving a prompt diagnosis. Prior reports of acute myeloid leukemia have revealed a strong association between the cup‐like nuclear morphology observed in bone marrow specimens and concurrent mutations of NPM1 and FLT3‐ITD. In cutaneous tissue sections of leukemia cutis, folded or indented nuclei may represent the "cup‐like" counterpart previously described in bone marrow specimens. Recognizing this morphological feature could aid in identifying this molecular subtype of leukemia cutis. In this study, we present a case of leukemia cutis in a 63‐year‐old female with AML and NPM1 and FLT3‐ITD mutations, demonstrating scattered indented/folded nuclei. [ABSTRACT FROM AUTHOR]

Key Clinical Message Clinical presentation of leukemia cutis (LC) is polymorphic and can reveal a malignant hemopathy. More commonly described in cases of acute myeloid leukemia (AML), LC can also occur in case of chronic myeloid leukemia (CML). Abstract Leukemia cutis is a rare form of extramedullary feature of malignant hemopathy, seldom associated with CML. Its clinical presentation is pleiotropic and differential diagnosis is broad. It relies on clinical and typical histological and biomolecular concordance. Once confirmed, treatment is based on that of the primary condition. We present a case of a leukemia cutis revealing a relapse of a CML successfully treated by tyrosine kinase inhibitor.

Key Clinical Message We report a case of leukemia cutis showing annular erythema during the course of Philadelphia chromosome‐positive acute B‐lymphoblastic leukemia. The annular appearance may be developed by immunomodulatory effects of blinatumomab.

Near early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a rare hematologic malignancy, for which second line therapeutic options are limited. T-cell leukemias are also rarely associated with leukemia cutis, which is more often seen in leukemias of myeloid origin. We present the case of an adult male diagnosed with near ETP-ALL, with IDH2 and DNMT3A mutations, suggestive of a myeloid origin, and leukemia cutis. After the patient progressed on hyper-CVAD and nelarabine, we treated him with the BCL-2 inhibitor venetoclax and the hypomethylating agent decitabine. The regimen induced a rapid bone marrow response and resolution of the leukemia cutis.

A 63-year-old woman presented with plaques covering 60 % body-surface-area and leonine facies. Blood work showed no diagnostic aberrancies. Skin biopsy contained a malignant CD4+/CD56+ mononuclear cell population concerning for blastic plasmacytoid dendritic cell neoplasm. A later bone marrow biopsy confirmed AML with KMT2A::MLLT10 fusion detected by next-generation sequencing (NGS). This patient's LC preceded blood and marrow based symptoms of AML. NGS of the initial skin biopsy should be considered as part of diagnostic guidelines in cases with LC in the differential as this may have led to earlier diagnosis in this case and future cases.

BackgroundInfant leukemia is a rare form of acute leukemia diagnosed prior to the age of 1 and is characterized by an extremely poor prognosis due to its dismal response to current therapeutic approaches. It comprises about 4% of all childhood cases of acute lymphoblastic leukemia (ALL). Isolated initial cutaneous involvement in ALL is uncommon, and even more so in infant ALL.Case presentationHere, we present the case of a 2-month-old healthy-appearing infant, initially presenting with a single scalp nodule and subsequently diagnosed with an infant ALL. The leukemia was characterized by the most immature B-lineage immunophenotype [pro-B ALL/B-I, according to the European Group for the Immunological Characterization of Leukaemias (EGIL) classification] and chromosomal translocation t(9;11)(p22;q23), resulting in fusion gene KMTLA2::MLLT3, which is considered a negative prognostic factor. The patient underwent hematopoietic stem cell transplantation and is still in remission.ConclusionsThis case is peculiar because of the rare occurrence of isolated initial cutaneous involvement in ALL. Despite the healthy appearance of the patient, every suspicious symptom suggestive of malignancies should be further investigated to anticipate the diagnosis and start treatment early.

Definitive radiation therapy is an effective local treatment for several cutaneous malignancies. Patients with diffuse or generalized skin manifestations might require total skin electron beam therapy (TSEBT) as an alternative treatment to the chasing technique. In this short communication, we highlight the evolving role of TSEBT and present its role in various forms of skin malignancies. [ABSTRACT FROM AUTHOR]

We describe a case of acute myeloid leukemia with NPM1 mutation and disseminated leukemia cutis in a very old patient, who achieved a long-lasting response to the azacitidine/venetoclax combination with molecular complete remission, given the potential value of this rarely observed clinical outcome. [ABSTRACT FROM AUTHOR]

Abstract Background In childhood acute lymphocytic leukemia (ALL), relapse is most commonly seen in the bone marrow (10–20%), followed by the central nervous system (3–8%). Isolated skin relapse is very rare in ALL. We report an 8-year-old child presented with isolated skin relapse. Case presentation An eight-year-old female patient presented with swelling on the scalp 3 months after the completion of the ALLIC-BFM 2009 chemotherapy protocol administered due to the diagnosis of precursor B-cell (pre-B) ALL. Physical examination revealed a hard, painless, hyperemic, nodule-shaped lesion measuring 2 × 1 cm on the right parietal bone. Atypical hematopoietic cells with the prominent nucleolus, narrow cytoplasm, and immunohistochemically stained with CD 10, 19, 22, 79-a, and TdT were observed in the histopathological examination of the skin lesion. There was no blast in the bone marrow aspiration smear and cerebrospinal fluid. The patient was diagnosed with aleukemic leukemia cutis (LC) and pre-B ALL, presenting as an isolated relapse. Conclusion Aleukemic LC is a very rare finding after leukemia treatment. It may present with various cutaneous lesions, such as a papule, macule, plaque, nodule, palpable purpura, and ulcerative lesions. Leukemia cutis should be considered in the differential diagnosis of skin lesions developing during or after treatment in children with leukemia.

Eccrine squamous syringometaplasia (ESS) is a histological term describing a mature squamous metaplasia of the eccrine ducts. Eccrine squamous syringometaplasia is not an infrequent histological finding and may be associated with chemotherapy or with a variety of non-specific conditions including infections, neoplastic conditions, and inflammatory skin diseases. We report a 75-year-old man who developed ESS within lesions of leukemia cutis (LC). The patient had an inaugural diagnosis of acute myeloid leukemia (AML) and he was not on chemotherapy when the biopsy was performed.

Key Clinical Message: We report a case of leukemia cutis showing annular erythema during the course of Philadelphia chromosome‐positive acute B‐lymphoblastic leukemia. The annular appearance may be developed by immunomodulatory effects of blinatumomab. [ABSTRACT FROM AUTHOR]

We highlight the utility of interferon regulatory factor 8 (IRF8), a novel marker of monocytic and dendritic cell lineages, in the diagnosis of a case of blastic plasmacytoid dendritic cell neoplasm (BPDCN) presenting initially in the skin. A 60‐year‐old male with a previous history of myelodysplastic syndrome presented with cutaneous nodules on chest and scalp. A punch biopsy specimen of a skin nodule showed a diffuse dermal infiltrate of atypical mononuclear cells. The neoplastic cells expressed CD4, CD56, CD43, and TdT but showed minimal reaction for TCL‐1 and CD123, and were negative for CD34, CD117, and MPO, confounding the diagnosis. IRF8 performed in retrospect was strongly positive. A new punch biopsy specimen of a chest nodule showed the blastoid tumor cells were positive for TCL‐1, CD4, and CD56, but dim CD123. Subsequent bone marrow involvement showed blastoid tumor cells with intense positivity for CD123, CD4, and CD56, which was supportive of the BPDCN diagnosis. BPDCN cases with weak or variable CD123 and TCL‐1 expression represent a potential diagnostic pitfall. In a recent study, 15 cases of BPDCN showed uniformly strong staining for IRF8, while CD123 was dim or negative in 4 of these 15 cases. We suggest IRF8 may be a useful marker for BPDCN, especially in cases with weak or variable expression of CD123 and TCL1. [ABSTRACT FROM AUTHOR]

Leukemia cutis (LC) is a dermatologic manifestation of leukemia. Its clinical implications for the patient and the biological mechanism behind the manifestation of LC are unknown. The oncology community is increasingly utilizing mutations to classify a number of malignancies to prognosticate outcomes and to choose targeted therapies. A single-center, retrospective analysis of dermatopathology cases with a diagnosis of leukemia cutis was performed. Patients with genetic testing using the Columbia Combined Cancer Panel (a targeted sequencing protocol of 467 genes) or Genoptix (targeted sequencing protocol of 44 genes) were identified. The frequency of the presence of genetic mutations in LC patients was compared to AML patients from the COSMIC (Catalogue of Somatic Mutations in Cancer) database. Twenty nine cases were confirmed to have leukemia cutis, 22 of which had acute myeloid leukemia (AML). Genetic testing was available in 11 patients. Twelve different mutations were observed with particular enrichment for NPM1 and FLT3-TKD. Our original hypothesis was that patients with LC would display a distinct mutation profile. Ultimately, the distribution of mutations observed in our cohort of LC patients largely reflects the mutational profile seen in AML patients in general.

Introduction: Cutaneous metastases represent 2% of skin tumors, with an overall incidence of 5.3%. Although rare, clinical presentations of cutaneous metastasis vary and can be mistaken for benign and malignant skin conditions. Methodology: This was a descriptive, retrospective review of all patients diagnosed with cutaneous metastasis seen at the Department of Dermatology from January 2013 to December 2019. Clinical and histopathologic data from the patients were collated from medical records, and slides were retrieved for review. Results: A total of 115 patients were included and 122 slides reviewed. There were more female than males, the mean age was 52.3 ± 14.0 years of age. The most common primary cancer was the breast, and accordingly, the most common location was anterior chest. Among the 122 slides reviewed from 104 patients, the most common histologic type was adenocarcinoma (72.1%), and showed the infiltrative pattern (26.2%). Other histologic types seen were melanoma (13.1%), leukemic infiltrates (11.5%), squamous origin (2.5%), and epithelioid sarcoma (0.8%). Lymphovascular invasion and dermal sclerosis were observed. Immunohistochemical stains were performed in only 13.9% of the cases. There was a high concurrence of the clinical with the histopathologic diagnosis (95.6%). Conclusion: Although rare, patients with cutaneous metastasis may present in dermatology clinics. Knowledge of clinical features and low threshold for doing biopsies may prove useful for these patients. Similarly, dermatopathologists should be able to recognize histologic features of cutaneous metastasis morphologically. Histologic features may be subtle and may be reminiscent of benign inflammatory conditions, hence judicious use of immunohistochemical staining is recommended.

A 6-year-old girl presented with recurrent skin rash at the initial stage, recent joint pain, and neutrophilia was found during a routine blood test. After a multidisciplinary case discussion, she was diagnosed with chronic neutrophil leukemia, and the symptoms were relieved after hydroxyurea and luxolitinib treatment. She received the allogeneic hematopoietic stem cell transplantation subsequently. At present, she is in stable condition and under follow-up. Chronic neutrophil leukemia is a rare disease, which rarely occurs in children. It is more difficult to diagnose in patients with skin rash as the first manifestation. The diagnosis and treatment of this case reflects the important role of multidisciplinary cooperation in the diagnosis and treatment of difficult and rare diseases.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare tumor that affects elderly individuals and presents a poor prognosis. Skin is the most common site of involvement, accounting for 89% of the cases. Extracutaneous organs, especially bone marrow, lymph nodes, and peripheral blood, can be involved at the time of diagnosis. We report a case of BPDCN in a child, presenting with a cutaneous lesion mimicking lymphoma or leukemia cutis. The histologic findings revealed a dense diffuse infiltration by monomorphic agranular medium-sized blast cells with sparing of the grenz zone, whose first immunophenotypic profile raised the possibility of diagnosing B lymphoblastic lymphoma or leukemia. However, the absence of CD10 expression and strongly positive expression for CD4, CD56, CD45RA, and the plasmacytoid dendritic cell-associated antigens, including CD123, supported the definite diagnosis of BPDCN. The patient responded well to a systemic combination chemotherapy regimen, modified from the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) protocol for anaplastic large cell lymphoma (ALCL), that differed from the established recommendation using ALL protocol. Owing to the patient’s excellent treatment outcome, this regimen could represent an effective alternative regimen for BPDCN in children.

Leukemia cutis represents infiltration of the skin by malignant leukocytes and typically presents as firm, red-brown papules and nodules. The bullous clinical subtype is considered a rare entity and can be a diagnostic challenge. This case describes a patient with bullous leukemia cutis mimicking vesiculobullous skin disease.

Introduction: Cutaneous metastases represent 2% of skin tumors, with an overall incidence of 5.3%. Although rare, clinical presentations of cutaneous metastasis vary and can be mistaken for benign and malignant skin conditions. Methodology: This was a descriptive, retrospective review of all patients diagnosed with cutaneous metastasis seen at the Department of Dermatology from January 2013 to December 2019. Clinical and histopathologic data from the patients were collated from medical records, and slides were retrieved for review. Results: A total of 115 patients were included and 122 slides reviewed. There were more female than males, the mean age was 52.3 ± 14.0 years of age. The most common primary cancer was the breast, and accordingly, the most common location was anterior chest. Among the 122 slides reviewed from 104 patients, the most common histologic type was adenocarcinoma (72.1%), and showed the infiltrative pattern (26.2%). Other histologic types seen were melanoma (13.1%), leukemic infiltrates (11.5%), squamous origin (2.5%), and epithelioid sarcoma (0.8%). Lymphovascular invasion and dermal sclerosis were observed. Immunohistochemical stains were performed in only 13.9% of the cases. There was a high concurrence of the clinical with the histopathologic diagnosis (95.6%). Conclusion: Although rare, patients with cutaneous metastasis may present in dermatology clinics. Knowledge of clinical features and low threshold for doing biopsies may prove useful for these patients. Similarly, dermatopathologists should be able to recognize histologic features of cutaneous metastasis morphologically. Histologic features may be subtle and may be reminiscent of benign inflammatory conditions, hence judicious use of immunohistochemical staining is recommended. [ABSTRACT FROM AUTHOR]

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare tumor that affects elderly individuals and presents a poor prognosis. Skin is the most common site of involvement, accounting for 89% of the cases. Extracutaneous organs, especially bone marrow, lymph nodes, and peripheral blood, can be involved at the time of diagnosis. We report a case of BPDCN in a child, presenting with a cutaneous lesion mimicking lymphoma or leukemia cutis. The histologic findings revealed a dense diffuse infiltration by monomorphic agranular medium-sized blast cells with sparing of the grenz zone, whose first immunophenotypic profile raised the possibility of diagnosing B lymphoblastic lymphoma or leukemia. However, the absence of CD10 expression and strongly positive expression for CD4, CD56, CD45RA, and the plasmacytoid dendritic cell-associated antigens, including CD123, supported the definite diagnosis of BPDCN. The patient responded well to a systemic combination chemotherapy regimen, modified from the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) protocol for anaplastic large cell lymphoma (ALCL), that differed from the established recommendation using ALL protocol. Owing to the patient's excellent treatment outcome, this regimen could represent an effective alternative regimen for BPDCN in children. [ABSTRACT FROM AUTHOR]

A 54‐year‐old man recently diagnosed with small lymphocytic lymphoma (SLL) had waxing and waning, indurated, erythematous plaques on his legs, with leukopenia and anemia disproportionate to the SLL burden in his marrow and pelvic lymph nodes. Punch biopsy of a plaque performed to evaluate for leukemia cutis revealed a lymphocytic lobular‐panniculitis‐like infiltrate resembling lupus panniculitis, but a preponderance of CD8+/Ki‐67+ T‐cells surrounding adipocytes raised concern for subcutaneous panniculitis‐like T‐cell lymphoma (SPTCL). Additional immunohistochemistry (IHC) studies showed that the adipotropic T‐cells expressed TCR‐gamma, supporting the rare, unexpected diagnosis of Primary cutaneous gamma‐delta T‐cell lymphoma (PCGDTCL). The patient subsequently met diagnostic criteria for hemophagocytic lymphohistiocytosis (HLH). PCGDTCL is an aggressive, HLH‐associated lymphoma requiring different management than SPTCL and SLL. This case illustrates how PCGDTCL can co‐exist with B‐cell lymphoma and resemble panniculitis on biopsies. PCGDTCL and SPTCL should enter the differential diagnosis whenever patients present with the constellation of lobular panniculitis and unexplained cytopenias. In the present case, close clinicopathologic correlation and judicious use of IHC on a small sample allowed for a prompt diagnosis. [ABSTRACT FROM AUTHOR]

Abstract Background Extramedullary manifestations (EM) are rare in acute myeloid leukemia (AML) and their impact on clinical outcomes is controversially discussed. Methods We retrospectively analyzed a large multi-center cohort of 1583 newly diagnosed AML patients, of whom 225 (14.21%) had EM. Results AML patients with EM presented with significantly higher counts of white blood cells (p

Myeloid sarcomas (MS) are rare extramedullary (EM) hematological tumors that generally arise during the natural course of acute myeloid leukemia (AML), occurring concomitantly with the onset of systemic leukemia; it can also occur following onset but rarely before. Common sites of EM involvement include the lymph nodes, skin, soft tissue, bone and peritoneum. Herein, we report the case of a 63-year-old man who presented EM AML upon initial diagnosis involving the bone marrow, lymph nodes and skin (leukemia cutis). A diagnosis was made based on immunohistochemistry (IHC). This case presents a diagnostic dilemma due to its atypical presentation and the sites involved. It also highlights the importance of IHC in the diagnosis of EM AML. The potential role of hypomethylating agents and Venetoclax in cases not eligible for hematopoietic stem cell transplant are also discussed.

Leukemia cutis (LC), a rare cutaneous manifestation of leukemia, can precede, follow, occur concurrently with, or present in the absence of (aleukemic) systemic leukemia. Leukemia cutis is especially rare as the presenting symptom of leukemia and is associated with a poor prognosis. Although more commonly seen in acute leukemias of myeloid and monocytic lineage, lymphocytic/lymphoblastic leukemias can also involve the skin. Three cases of LC presented with diverse skin lesions ranging from an erythematous rash to violaceous macules and papules to subcutaneous nodules. One case clinically mimicked fixed drug eruption. All the patients had acute myeloid leukemia (AML). Lesions showed two overarching histologic patterns: atypical perivascular infiltrate or nodular dermal histiocytoid infiltrate. Our cases expressed myeloperoxidase (MPO), a helpful marker to distinguish myeloid from non-myeloid cells, and CD68, a monocytic marker frequently expressed in cutaneous AML. CD14, a marker of monocyte maturity, was negative. In the absence of systemic leukemia, common diagnostic tools for hematologic malignancies such as bone marrow biopsy and flow cytometry are non-contributory, making morphologic and immunohistochemical analysis of the skin lesions key to diagnosis.

Abstract A patient living with HIV developed disseminated erythematous plaques and the biopsy was consistent with hematological neoplasm infiltration. Further evaluation revealed hepatosplenomegaly, anemia, thrombocytopenia, and leukocytosis, with 33% myeloblasts. Bone marrow assessment confirmed acute myelomonocytic leukemia, with NPM1 mutation. The patient was treated with a conventional induction regimen obtaining complete remission.

Background: Genomic landscape of extramedullary acute myeloid leukemia (EM‐AML), including myeloid sarcoma (MS) and leukemia cutis (LC), is not well characterized. The potential utility of next‐generation sequencing (NGS) using EM tissue is not established. Methods: In this multicenter retrospective study, clinical and NGS data were collected on patients with EM‐AML. All statistical analyses were performed in SPSS Statistics (v 26). Results: Our study included 58 patients with EM‐AML. The median age at diagnosis was 62 years; 59% of patients had MS and 33% had LC. EM‐AML was isolated (i.e., without blood or marrow involvement) in 31% and was first noted at relapse in 60% of patients. Median overall survival in our cohort was 18.2 months overall, with 19.1 months and 11.6 months in the newly diagnosed and the relapsed/refractory patients, respectively. At least one targetable or potentially targetable alteration was present in 52% of patients with EM‐site NGS, with 26% IDH1, 21% NPM1, 11% IDH2, 6% FLT3, and 13% KMT2A‐PTD. Mutations in IDH1 were significantly more prevalent on NGS from EM tissue than non‐EM (blood or marrow) samples (26% vs. 3%; p =.030). Three of four patients treated with IDH inhibitors based on EM‐site NGS experienced a complete response. Conclusions: Targetable mutations are frequent in EM‐AML and EM‐site NGS is warranted for selecting potential targeted therapies for patients with EM‐AML. Next‐generation sequencing (NGS) on extramedullary (EM) tissue revealed at least one potentially targetable alteration in 52% of patients with EM acute myeloid leukemia treatment with IDH inhibitors led to complete response in three of four patients with IDH1 or IDH2 mutations identified on EM‐site NGS. [ABSTRACT FROM AUTHOR]

We report a rare manifestation of cutaneous borreliosis in a patient with pre-existing malignant lymphoproliferative disease, in particular chronic lymphocytic B cell leukemia (B-CLL). The patient's cutaneous lesions were initially diagnosed histologically as leukemia cutis. Distribution pattern of the skin lesions were in typical localizations for borrelial lymphocytoma. Borrelia burgdorferi sensu stricto was isolated and cultured from two sites (ear, mammilla). Antibiotic therapy improved the cutaneous lesions and the general condition of the patient. However, a second round of antibiotic therapy was required to resolve the lesions. At eleven years of follow-up the patient's skin was clear and she still had a stable condition of B-CLL without chemotherapy. In conclusion, the patient suffered from Lyme borreliosis ( Borrelia lymphocytoma) and the cutaneous symptoms were aggravated by the underlying condition of chronic B-CLL condition., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hofmann, Margos, Todorova, Ringshausen, Kuleshov and Fingerle.)

Objectives: Leukemia cutis is a conflicting term to describe neoplastic hematopoietic infiltrates in the skin. Cutaneous myeloid or lymphoid proliferations often present a serious differential diagnostic challenge for pathologists., Methods: This review aims to outline the confusion associated with the term leukemia cutis and discuss in detail the foremost common differential diagnoses in daily practice. The review is based on a summary of the relevant literature as well as on the authors' experience., Results: It addresses precursor cell myeloid and lymphoid tumors that are strictly considered true leukemia cutis but also more mature neoplasms, including some recently described mature extramedullary myeloid proliferations. Finally, a practical, comprehensive stepwise approach combining traditional immunohistochemical marker panels, novel lineage- or mutational-specific markers, and other ancillary tests is suggested to reach an entity-specific diagnosis., Conclusion: The proper combination of ancillary techniques can help the pathologist to provide an accurate diagnosis of these challenging skin lesions., (© American Society for Clinical Pathology, 2024.)

Abstract Leukemia cutis is a cutaneous manifestation of leukemia. Herein, we present a rare cutaneous manifestation of leukemia cutis in a patient with myeloid leukemia m5, characterized by hyperpigmented red‐to‐brown patches on face and upper trunk. To our knowledge, hyperpigmented patches secondary to leukemia cutis is rarely described in the literature.

Chronic neutrophilic leukemia (CNL) is a rare BCR-ABL negative myeloproliferative neoplasm that usually affects older adults with a poor prognosis. Leukemia cutis is an extramedullary manifestation of leukemia and may be misdiagnosed by dermatologists. Here, we describe a case of CNL in a 6-year-old Chinese girl with leukemia cutis as the first manifestation. Her skin rashes failed to attract the attention of dermatologists in early stages. The diagnosis was confirmed by peripheral smear, bone marrow studies, genomic analysis and skin biopsy.

Acute myeloid leukemia (AML) arises from clonal expansion of malignant hematopoietic precursor cells in the bone marrow. In rare instances, AML can recur with prominent extramedullary manifestations (i.e., leukemia cutis or myeloid sarcoma), either simultaneously or preceding marrow involvement, or as a sole site of primary disease relapse. [ABSTRACT FROM AUTHOR]

Background: Cutaneous hematologic malignancies are rare in children, and the literature about them is still sparse. Objective: The purpose of our study was to report our experience with pediatric cases of cutaneous hematologic disorders and describe their clinical and histological features. Methods: Data were retrospectively collected from the histopathologic database of the CHU Sainte-Justine, University of Montreal, Montreal, Canada. All patients up to 18 years of age with a diagnosis of a primary cutaneous lymphoma (including lymphomatoid papulosis), secondary cutaneous lymphoma or cutaneous manifestations of leukemia, followed from 1980 to 2019 at our center were reviewed. Results: Thirty-six patients were included. Age at presentation ranged from birth to 18 years of age (mean 7.83 ± 5.16; median 7.0). Ten different hematologic disorders were identified according to the WHO-EORTC classifications: lymphomatoid papulosis (10 cases), mycosis fungoides (6 cases), anaplastic large cell lymphoma (4 cases), pre-B acute lymphoid leukemia (5 cases), primary cutaneous marginal zone B-cell lymphoma (4 cases), primary cutaneous CD4+medium T-cell lymphoproliferative disorder (1 case), extranodal NK/T-cell lymphoma (1 case), hydroa vacciniforme-like lymphoproliferative disorder (1 case), B-cell lymphoblastic lymphoma (1 case) and acute myeloid leukemia (3 cases). Conclusion: The most common subtype of cutaneous hematologic disease in our single institution study was lymphomatoid papulosis (type A and type C), followed by mycosis fungoides. Recognition of this large clinical and histological spectrum by dermatologists is important because diagnosis is often established by biopsy of skin lesions, even in secondary cutaneous cases. Moreover, the clinicopathological correlation is of utmost importance for the final diagnosis of those pathologies. [ABSTRACT FROM AUTHOR]

Myeloid sarcomas (MS) are rare extramedullary (EM) hematological tumors that generally arise during the natural course of acute myeloid leukemia (AML), occurring concomitantly with the onset of systemic leukemia; it can also occur following onset but rarely before. Common sites of EM involvement include the lymph nodes, skin, soft tissue, bone and peritoneum. Herein, we report the case of a 63-year-old man who presented EM AML upon initial diagnosis involving the bone marrow, lymph nodes and skin (leukemia cutis). A diagnosis was made based on immunohistochemistry (IHC). This case presents a diagnostic dilemma due to its atypical presentation and the sites involved. It also highlights the importance of IHC in the diagnosis of EM AML. The potential role of hypomethylating agents and Venetoclax in cases not eligible for hematopoietic stem cell transplant are also discussed. [ABSTRACT FROM AUTHOR]

Multiple papulonodular skin lesions at birth can indicate the presence of various benign and malignant disorders. Although the lesions’ clinical aspect (color and consistency, in particular) may steer the clinician towards one disorder or another (infantile myofibromatosis, xanthogranuloma, or metastatic neuroblastoma), the diagnosis can only be confirmed by the histopathologic assessment of a biopsy. In neonates, a rapid but accurate diagnosis is critical because skin lesions may be the first manifestation of a malignant disorder like leukemia cutis or metastatic neuroblastoma. Here, we review the various disorders that may manifest themselves as multiple skin lesions at birth.

Leukemia cutis is a comprehensive terminology for dermal manifestations of any type of leukemia either with accompanied or antecedent blood or bone marrow involvement. Although both myeloid and lymphoid neoplastic leukocytes can infiltrate the skin, the frequency is higher among children with congenital myeloid leukemia. However, the underlying pathogenesis of dermal tropism is not yet established. Clinical manifestation varies regarding appearance, site, and numbers. Skin biopsy is essential for the early establishment of the diagnosis and to guide for further testing and categorical management. We report the case of acute myeloid leukemia-cutis in a 22-year-old female where cutaneous manifestation preceded the hematological diagnosis of systemic leukemia. [ABSTRACT FROM AUTHOR]

Leukemia cutis (LC) is an extramedullary manifestationof leukemia owing to cutaneous infiltration ofneoplastic cells resulting in characteristic firm,erythematous nodules. Most cases of LC occur inpatients with acute myelogenous leukemia andchronic myelogenous leukemia. However in rarecases, LC has presented in patients with acutelymphoblastic leukemia (ALL). In these rare ALLassociatedcases, only 10 cases of precursor-B-ALL(pre-B-ALL) have been described in the literature.We report a case of a 22-year-old man with relapsingpre-B-ALL who presented with a 4-day history ofmultiple asymptomatic, soft, dome-shaped, lipomalikemounds on his scalp and chin, which exhibitedcutaneous involvement by leukemic cells. To date, thisis the first case of pre-B-ALL associated leukemia cutispresenting as soft, dome-shaped mounds resemblinglipomas.

Leukemia cutis (LC) is the cutaneous infiltration of neoplastic cells rarely seen with acute lymphocytic leukemia. We report the case of a young female presenting with a morpheaform plaque on the face, subsequently diagnosed with B-cell acute lymphoblastic leukemia (ALL) and LC, on histopathology and immunohistochemistry. Among the limited cases of LC reported with B-cell ALL, such an atypical presentation has previously never been reported.