Cytophagic and S‐100 protein immunoreactive myeloid leukemia cutis

Myeloid leukemia cutis (LC) is the cutaneous involvement by neoplastic leukocytes of the myeloid series. Myeloid LC may occur de novo or concurrently with acute myeloid leukemias, chronic myeloid leukemias, other myeloproliferative disorders or myelodysplastic syndromes. We describe an unusual case of cytophagic S‐100 protein immunoreactive leukemia cutis presenting in an 87‐year‐old woman without prior history of myeloid leukemia or other hematologic disorders. We outline key histologic and immunohistochemical features that aide in the diagnosis of LC. The presence of cytophagocytosis on histologic examination, a phenomenon more commonly associated with lymphoid rather than myeloid malignancies, provided a clue to the possibility of a malignant process. The atypical myeloid infiltrate showed S‐100 protein positivity, an unusual finding that may be seen in LC. Although not commonly reported in LC, the presence of S‐100 protein positivity and cytophagocytosis should not lead to the premature exclusion of LC as a possible diagnosis until a thorough clinical, histologic and immunohistochemical evaluation is performed. In addition, the presence of cytophagocytosis has been shown to have prognostic significance for patients with myeloid leukemia. Thomas CG, Patel RM, Bergfeld WF. Cytophagic and S‐100 protein immunoreactive myeloid leukemia cutis.     

Disseminated De Novo Myeloid Sarcoma in a 17‐year‐old Boy

Myeloid sarcoma (MS) is a rare extramedullary tumor of malignant myeloid cells often associated with acute myeloid leukemia. We report a case of a 17‐year‐old boy presenting with diffuse red‐brown skin nodules ultimately diagnosed with the scarcely described disseminated, de novo MS. It is important for dermatologists to keep MS on their differential when assessing patients with disseminated red‐brown nodules.     

Cutaneous presentation preceding acute myeloid leukemia with CD4+/CD56+ expression misdiagnosed as a blastic plasmocytoid dendritic cell neoplasm: A case report

Acute myeloid leukemia (AML) may initially present as cutaneous lesions corresponding to blasts involving the skin as the first clinical manifestation prior to blood and bone marrow (BM) infiltration. Such presentation is known as myeloid leukemia cutis (LC). Blastic plasmocytoid dendritic cell neoplasm (BPDCN) is an aggressive tumor derived from the precursors of plasmocytoid dendritic cells with cutaneous and BM involvement and leukemic dissemination. Myeloid LC and BPDCN may be difficult to distinguish as they share similar clinical and histopathological features, in particular AML with monocytic differentiation. Nevertheless, the correct diagnosis has to be made to determine adequate and effective therapy. Here, we report the case of a 61‐year‐old woman who presented with an AML with MLL rearrangement and CD4+/CD56+ expression presenting as LC and that was misdiagnosed as BPDCN. We emphasize that careful and exhaustive analyses should be performed to make the correct diagnosis.     

Papuloerythroderma‐like cutaneous involvement of a CD62L− subclone of T‐cell prolymphocytic leukemia

We report the case of an 88‐year‐old Japanese man with erythrodermic involvement of T‐cell prolymphocytic leukemia (T‐PLL). He had a history of pharyngeal diffuse large B‐cell lymphoma successfully treated with polychemotherapy including cyclophosphamide and epirubicin, 6 years before the current illness. He presented with numerous reddish, coalescing, flat‐topped papules on the trunk and extremities, sparing the skin folds of the abdomen, the features of which mimicked those of papuloerythroderma. Immunohistochemistry showed perivascular and epidermotropic infiltration of CD3⁺ CD4⁺ T cells in the cutaneous lesion. However, flow cytometric analysis revealed that the skin infiltrating T cells were negative for surface CD4, and that CD3⁺ CD4^? CD8^? cells made up 92% of the T‐cell fraction of peripheral blood. The circulating atypical T cells had a round or oval nucleus and prominent nucleoli, and the deletion of chromosomes 6q, 13 and 17. These cytological profiles were consistent with those of T‐PLL and distinct from those of Sézary cells. The same T‐cell clone was detected in the cutaneous lesion and peripheral blood, but the expression of CD62L was absent in the skin infiltrates and present in the circulating cells. No specific mutation was detected in STAT3 or STAT5B. Although low‐dose oral etoposide had a beneficial effect on the skin rash, a fatal crisis of marked leukocytosis (169 × 10³/μL) occurred 19 months after the illness onset. CD62L‐leukemic cells of T‐PLL may infiltrate the skin to form papuloerythroderma‐like cutaneous lesions.     

Cutaneous accumulation of plasmacytoid dendritic cells associated with acute myeloid leukemia: a rare condition distinct from blastic plasmacytoid dendritic cell neoplasm

A cutaneous infiltrate composed of plasmacytoid dendritic cells may occasionally occur in a patient suffering from a myeloid neoplasm. To date, the clinical and pathological features associated with this event remains poorly characterized. Herein, we report a patient with acute myeloid leukemia who developed pruritic papules or erythematous plaques scattered on the skin. Microscopic examination showed a dermal infiltrate rich in plasmacytoid dendritic cells expressing CD4, CD43, CD68, granzyme B, CD123, CD303 [blood dendritic cell antigen 2 (BDCA-2)], CD2-associated protein (CD2AP) and T-cell leukemia/lymphoma oncogene 1 (TCL1). Our observation illustrates further that cutaneous lesions associated with some myeloid neoplasms, especially those featuring a monocytic component, may be composed of plasmacytoid dendritic cells. Because of differences in clinical, pathological and genetic features, this rare condition should be distinguished from blastic plasmacytoid dendritic cell neoplasm.     

JAK2‐positive cutaneous myelofibrosis presenting as sclerosing extramedullary hematopoietic tumors on the scalp: case presentation and review of the literature

We report the second case of cutaneous myelofibrosis with a documented JAK2 activating mutation involving the scalp of a 67‐year‐old woman with primary myelofibrosis in her marrow. In contrast to the previous case, the biopsy revealed extensive lesional collagen deposition and closely mimicked a fibrohistiocytic proliferation. Similar rare lesions occurring in the setting of myeloproliferative neoplasms have been called sclerosing extramedullary hematopoietic tumors. These entities appear histomorphologically and etiologically distinct from extramedullary hematopoiesis, and their diagnosis should prompt the workup for a myeloproliferative neoplasm in the absence of an antecedent diagnosis. The presence of the JAK2 mutation in our case confirmed that the lesions represented skin involvement by a neoplastic myeloid proliferation and not compensatory extramedullary hematopoiesis. Our patient died of disease several months following the appearance of her lesions, which is in keeping with other reports that suggest that cutaneous myelofibrosis may serve as an independent poor prognostic sign in otherwise advanced primary myelofibrosis. A review of the literature further emphasizes the importance of distinguishing this entity from mesenchymal neoplasms and acute myeloid leukemia involving the skin.     

Clinical and pathological features of myeloid leukemia cutis

BackgroundMyeloid leukemia cutis is the terminology used for cutaneous manifestations of myeloid leukemia.ObjectiveThe purpose of this study was to study the clinical, histopathological and immunohistochemical features of myeloid leukemia cutis.MethodsThis was a retrospective study of clinical and pathological features of 10 patients with myeloid leukemia cutis.ResultsOne patient developed skin lesions before the onset of leukemia, seven patients developed skin infiltration within 4-72 months after the onset of leukemia, and two patients developed skin lesions and systemic leukemia simultaneously. Of these patients, five presented with generalized papules or nodules, and five with localized masses. The biopsy of skin lesions showed a large number of tumor cells within the dermis and subcutaneous fat layer. Immunohistochemical analysis showed strong reactivity to myeloperoxidase (MPO), CD15, CD43 and CD45 (LCA) in most cases. NPM1 (nucleophosmin I) and FLT3-ITD (Fms-like tyrosine kinase 3-internal tandem duplication) mutations were identified in one case. Five patients with acute myelogenous leukemia and one patient with chronic myelomonocytic leukemia died within two months to one year after the onset of skin lesions.Study limitationsThis was a retrospective and small sample study.ConclusionsIn patients with myelogenous leukemia, skin infiltration usually occurs after, but occasionally before, the appearance of hemogram and myelogram abnormalities, and the presence of skin infiltration is often associated with a poor prognosis and short survival time. myeloid leukemia cutis often presents as generalized or localized nodules or masses with characteristic pathological and histochemical findings.     

CD30+ clonal T‐cell lymphoid proliferation of the skin in a patient with hypereosinophilic syndrome

We report a hitherto undescribed unusual CD30+ clonal T‐cell proliferation in a 46‐year‐old man with the lymphocytic variant of hypereosinophilic syndrome with a 17‐year history of pruritus, generalized persistent papulonodular skin lesions and peripheral blood hypereosinophilia. A skin biopsy showed an eosinophil‐rich infiltrate with small to medium‐sized CD30+ lymphocytes and Churg‐Strauss granulomas. Peripheral blood flow cytometry revealed an aberrant T‐cell clone which, molecular genetically, was identical to the T‐cell clone detected in the skin. No genetic aberrations of platelet‐derived growth factor receptor alpha (PDGFRA), FIP1L1‐PDGFRA, PDGFRB or FGFR1 were found. The skin lesions showed transient response to systemic and topical corticosteroids. The skin lesions represent cutaneous involvement by clonal T‐cells in hypereosinophilic syndrome and differ from known cutaneous CD30+ lymphoproliferative disorders.     

Tumor‐forming plasmacytoid dendritic cells associated with myeloid neoplasms. Report of a peculiar case with histopathologic features masquerading as lupus erythematosus

Plasmacytoid dendritic cells (PDC) belong to a subtype of dendritic cells that are normally absent in healthy skin. In some inflammatory diseases of the skin, especially lupus erythematosus (LE), these cells are occasionally recruited in great amounts, which can be used as a helpful clue for diagnosis. Rarely, PDC may also accumulate in the skin of patients with myeloid leukemia, a yet poorly known condition currently called ‘tumor‐forming PDC associated with myeloid neoplasms’. In this study, we describe a patient with unsuspected chronic myelomonocytic leukemia who developed cutaneous lesions characterized by a dermal infiltrate rich in PDC. Similarly to LE, such neoplastic PDC were accompanied by interface dermatitis‐like changes, but displayed an aberrant phenotype and shared the same chromosomal abnormality with the leukemic cells identified in the bone marrow, thus revealing the neoplastic nature of the process. This observation illustrates that tumor‐forming PDC associated with myeloid neoplasms may microscopically mimic LE in some patients. Accordingly, a hematologic workup is recommended in any skin lesion featuring excessive numbers of PDC, even if morphological alterations suggestive of interface dermatitis are found.     

Extramedullary acute leukemia developing in a pre‐existing osteoma cutis

Primary osteoma cutis (cutaneous ossification) is an uncommon disease in which there is bone formation within the skin in the absence of a demonstrable pre‐existing condition. Osteoma cutis is a chronic and benign condition. We report a case of a 45‐year‐old man who developed extramedullary acute leukemia with a myeloid immunophenotype (myeloid sarcoma) with its initial presentation within an isolated pre‐existing osteoma cutis in the post‐auricular scalp without evidence of systemic acute leukemia or chronic myeloid stem cell disorders. The tumor was surgically excised without complications. Four months later, acute leukemia recurred in the contralateral posterior mandible and showed an immunophenotype consistent with acute lymphoblastic leukemia/lymphoma. The patient now has been treated by standard protocols for acute leukemia. The diagnosis of an extramedullary acute leukemia is challenging because of its inconsistent clinical and histopathologic presentations. Extramedullary acute leukemia developing in a pre‐existing osteoma cutis is very unusual and has not been previously reported in the literature.     

Human T‐lymphotropic virus 1 (HTLV‐1)‐associated lichenoid dermatitis induced by CD8+ T cells in HTLV‐1 carrier,HTLV‐1‐associated myelopathy/tropical spastic paraparesis and adult T‐cell leukemia/lymphoma

Human T‐lymphotropic virus type 1 (HTLV‐1) induces adult T‐cell leukemia/lymphoma (ATLL), HTLV‐1‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) and carrier. ATLL is a mature CD4⁺CD25⁺CCR4⁺ T‐cell neoplasm, and approximately half of patients have direct skin involvement manifesting patch, plaque, tumor, multiple papules, erythroderma and purpura. However, there exist secondary eruptions without tumor cell infiltration in patients with ATLL or HAM/TSP and carriers of HTLV‐1. To clarify the presence of reactive skin eruptions in HTLV‐1‐infected individuals, we reviewed our patients with HTLV‐1‐associated diseases. In 2002–2012, we saw 50 ATLL or HAM/TSP patients and HTLV‐1 carriers presenting with skin lesions. We retrospectively selected cases that histologically showed lichenoid tissue reactions with predominant infiltration of CD8⁺ T cells, but not CD4⁺ tumor cells. The cases included erythroderma (HTLV‐1 carrier), lichen planus (HTLV‐1 carrier), alopecia areata (HAM/TSP), chronic actinic dermatitis (HTLV‐1 carrier to acute ATLL conversion) and discoid lupus erythematosus (smoldering ATLL). They were graft‐versus‐host disease‐like, major secondary lesions and seen in HTLV‐1 carriers and patients with HAM/TSP and smoldering ATLL. We coin the term HTLV‐1‐associated lichenoid dermatitis (HALD) to encompass the conditions. HALD may occur in association with the elevated immunity toward HTLV‐1‐infected CD4⁺ T cells, thus sharing the pathogenetic role of cytotoxic T cells with HAM/TSP.     

Myeloid sarcoma in a newborn: A rare manifestation of congenital acute myeloid leukemia

Cutaneous myeloid sarcoma is rarely present prior to the diagnosis of congenital acute myeloid leukemia (AML); the former is typically diagnosed with or after the leukemia. We report a 2-day-old male born with multiple cutaneous red to violaceous nodules. Histopathologic and immunohistochemistry findings from a skin nodule were suspicious for myeloid sarcoma. Bone marrow biopsy was initially negative for aberrant blasts; however, at age 4 months, AML with a KMT2A gene rearrangement was identified via bone marrow biopsy.     

Olmsted syndrome in an Iranian boy with a new de novo mutation in TRPV3

Olmsted syndrome (OS) is a rare congenital skin disorder characterized by palmoplantar keratoderma, periorificial hyperkeratotic lesions and alopecia. Constriction of digits, onychodystrophy and pruritus may also occur. Recently, pathogenic heterozygous mutations in TRPV3 were identified, with most cases showing de novo dominant inheritance. We present the clinical and molecular features of OS in a 10‐year‐old Iranian boy. He had mutilating palmoplantar keratoderma, periorificial keratotic plaques, diffuse alopecia and constriction bands (pseudoainhum), which led to autoamputation of two digits. TRPV3 was sequenced and a new de novo heterozygous missense mutation, c.2076G>C (p.Trp692Cys), was identified. This case illustrates the characteristic clinical features and complications that can present in OS, and further expands the molecular basis of this genodermatosis.     

The atopic skin‐like microenvironment modulates the T‐cell‐polarising cytokine production of myeloid dendritic cells,as determined by laser scanning cytometry

Because it is not known exactly when or where myeloid dendritic cells (mDCs) acquire their atopic dermatitis (AD)‐specific T‐cell‐polarising ability in patients with this condition, we used laser scanning cytometry (LSC) to determine whether isolated peripheral blood mDCs from AD patients differed from cells from controls in their cytokine expression profiles de novo and after stimulation with Staphylococcus enterotoxin B (SEB) and thymic stromal lymphopoietin (TSLP), which represents an AD‐like microenvironment. Unstimulated mDCs from AD patients showed pluripotent T‐cell‐polarising capacity, and the surrounding skin microenvironment was essential for the distinctive, disease‐specific activity of mDCs (Th2‐Th22 bias). We also emphasise that LSC is an attractive technique to study the effect of new DC‐targeted therapeutic modalities in AD.     

Epstein–Barr virus‐positive diffuse large B‐cell lymphoma in an elderly patient

Epstein–Barr virus‐positive (EBV) diffuse large B‐cell lymphoma (DLCBL) of the elderly is a newly described lymphoproliferative disorder that arises in elderly patients without a predisposing immunodeficiency. Clinical features at presentation may include lymphadenopathy, B‐symptoms and extranodal involvement. The main sites of extranodal involvement are the skin, lung, tonsil and stomach. Histopathological findings include atypical large lymphoid cells with variable amounts of reactive cells, such as small lymphocytes, plasma cells and histiocytes. The neoplastic cells are positive for CD20, and in situ hybridization for EBV‐encoded RNA is positive in the majority of neoplastic cells. We present a new case of EBV‐positive DLBCL in an 85‐year‐old man, who presented to our clinic with a 2‐month history of asymptomatic cutaneous lesions involving his face and scalp.     

Neurotropic T‐cell lymphocytosis: a cutaneous expression of CLIPPERS

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is an inflammatory disease of the central nervous system that predominantly involves the pons and cerebellum and that improves with immunosuppressive treatment. Only recently described, the etiology is unknown, diagnosis is difficult and long‐term neurological sequelae may occur without aggressive treatment. Herein, we describe a 59‐year‐old woman who presented with subcutaneous nodules affecting her face, trunk, limbs and an indurated annular erythematous lesion on her forearm. This was associated with marked dysesthesia of her skin, refractory to treatment. There was a 4‐year history of dysequilibrium, vertigo, truncal and gait ataxia with progressive neurological symptoms. Skin biopsy of the annular nodular lesion showed a lymphohistiocytic infiltrate in dermis and subcutis with a striking lymphocyte‐dominant infiltrate that was perineural and formed a nodular collection extending along a prominent subcutaneous nerve. Immunophenotyping indicated a marked predominance of T cells that were CD3 positive with a 2 : 1 CD4 : CD8 ratio. Scattered histiocytes were present but no well‐formed granulomas or vasculitis. Magnetic resonance imaging studies showed changes in the pontine, brain stem and cerebellar region, which subsequently were defined as characteristic for CLIPPERS, but no brain biopsy was pursued. The marked neural skin symptoms and the cutaneous histopathological findings indicate that the skin may be an additional target organ in CLIPPERS, and the immune response may be directed against a common neural antigen. In radiologically typical CLIPPERS, identification of clinical skin lesions particularly subcutaneous nodules and biopsy may potentially form a basis for tissue diagnosis in this syndrome.     

Leukemic cells within skin lesions of psoriasis in a patient with acute myelogenous leukemia

We report on an 81-year-old man with acute myelo-monocytic leukemia (FAB M4) and a long-standing history of psoriasis. Biopsy of psoriatic plaques revealed the coexistence of characteristic histopathologic aspects of psoriasis together with an infiltrate of blasts with features of myelo-monocytes, suggestive of a specific leukemic infiltrate within plaques of psoriasis. Immunohistologic stainings showed positivity of blasts for LN2 (CD74), MT1 (CD43), and lysozyme, consistent with a myeloid lineage of these cells. To the best of our knowledge, this is the first report on the association of psoriasis with myelogenous leukemia. The presence of leukemic cells within psoriatic skin plaques may be explained by non-specific recruitment of recirculating malignant cells to the skin. Alternatively, as psoriasis is an inflammatory disease involving granulocytes among other cell types, it may be hypothesized that leukemic cells retain to some extent their capability to respond to physiologic stimuli and enter the skin in response to specific chemotactic factors.     

Mast cells protect from skin tumor development and limit tumor growth during cutaneous de novo carcinogenesis in a Kit‐dependent mouse model

Epidermal tumors belong to the most frequent type of neoplasms, and tumor‐associated accumulation of mast cells (MCs) has first been observed more than a century ago. Therefore, MCs have been implicated in tumor development and growth; however, the results regarding the role of MC in cutaneous de novo carcinogenesis are still controversially discussed. Here, we subjected MC‐deficient Kit^W/Kit^W?v mice to chemical skin carcinogenesis. Tumors were induced using the carcinogen 7,12‐dimethylbenz[a]‐anthracene and subsequent treatment with the tumor promoter 12‐tetradecanoyl‐phorbol‐13‐acetat. The treatment resulted in pronounced inflammatory cell infiltrates that were diminished in MC‐deficient animals. Unexpectedly, tumor development and growth was significantly increased in MC‐deficient Kit^W/Kit^W?v mice. The repair of their MC deficiency by local adoptive transfer of MCs normalized tumor incidence and growth. The recruitment of skin‐infiltrating immune cells, particularly of F4/80+ monocytes, Gr‐1+ granulocytes, B220+ B cells and CD8+ T lymphocytes, to sites of tumor development was, in part, also controlled by MCs. Recent evidence indicated the importance of local antitumor tissue immunity which prevents tumor development. These findings suggest a critical role for MCs in mediating these host antitumor immune responses in the skin.     

Acneiform primary cutaneous CD4‐positive small/medium pleomorphic T‐cell lymphoma with prominent necrosis

Primary cutaneous CD4‐positive small/medium pleomorphic T‐cell lymphoma (SMPTCL) is an indolent form of cutaneous lymphoma that usually presents in solitary fashion and is histopathologically characterized by nodular infiltration of small‐ to medium‐sized pleomorphic T‐cells. We report the case of a patient who presented with a 5‐year history of acneiform lesions on his face. Histopathologic examination of two lesions revealed a nodular infiltrate of small to medium‐sized lymphocytes with necrosis in the dermis. The proliferating cells were positive for CD2, CD3 and CD4 and negative for CD8, CD30 and CD56. They were positive for TIA‐1 and negative for perforin and granzyme B. The Ki67 proliferation index was approximately 10%. The neoplastic cells expressed programmed death‐1 and lacked expression of CXCL‐13, bcl‐6 and CD10. In situ hybridization for Epstein–Barr virus‐encoded RNA yielded a negative result. T‐cell receptor gene rearrangement showed identical T‐lymphocyte monoclonality in both lesions. In brief, we report a rare case of acneiform SMPTCL with prominent necrosis.     

Differentiation syndrome during ivosidenib treatment with immunohistochemistry showing isocitrate dehydrogenase R132H mutation

We report a case of differentiation syndrome in a patient receiving the IDH1 inhibitor ivosidenib, with skin biopsy showing isocitrate dehydrogenase (IDH) R132H-mutated leukemia cutis. A 72-year-old man with IDH1-mutated acute myeloid leukemia (AML), status-post allogeneic cell transplantation, on ivosidenib for 6 months, was admitted for culture-negative neutropenic fever, pink and purpuric plaques and patches on the legs, abdomen and back, edema, hypotension, and shortness of breath. Skin biopsy revealed an infiltrate of atypical, immature, myeloperoxidase-positive mononuclear cells compatible with leukemia cutis or Sweet syndrome. Although dermal edema and interstitial neutrophilic infiltrate with karyorrhexis characteristic of Sweet syndrome were not seen, the atypical cells lacked expression of CD117 and CD34, which were expressed in the original leukemia. Additional immunohistochemical staining of suspected blasts was strongly positive for IDH1 R132H, suggesting a diagnosis of leukemia cutis. As the immunophenotype of blasts in skin infiltrates can significantly differ from the immunophenotype seen in blood and bone marrow, this case shows that mutation-specific antibodies such as anti-IDH1 R132H may be useful to help distinguish malignant from non-malignant infiltrates in the skin. Furthermore, differentiation syndrome may show histopathologic features of leukemia cutis on skin biopsy.