Untying the Gordian knot of composite hemangioendothelioma: Discovery of novel fusions.

Composite hemangioendothelioma is a rare, locally aggressive, and rarely metastasizing vascular neoplasm which affects both children and adults. Recently, a number of gene fusions including YAP1::MAML2, PTBP1::MAML2, and EPC1::PHC2 have been detected in a small subset of cases with or without neuroendocrine expression. Herein, we present four additional cases with novel in-frame fusions. The cohort comprises two females and two males with a wide age range at diagnosis (24-80 years). Two tumors were deep involving the right brachial plexus and mediastinum, while the remaining were superficial (right plantar foot and abdominal wall). The size ranged from 1.5 to 4.8 cm in greatest dimension. Morphologically, all tumors had an admixture of at least two architectural patterns including retiform hemangioendothelioma, hemangioma, epithelioid hemangioendothelioma, or angiosarcoma. The tumors were positive for endothelial markers CD31 (3/3), ERG (4/4), and D2-40 (1/4, focal), while SMA was expressed in 2/3 highlighting the surrounding pericytes. Synaptophysin showed immunoreactivity in 2/3 cases. One patient had a local recurrence after 40 months, while two patients had no evidence of disease 4 months post-resection. Targeted RNA sequencing detected novel in-frame fusions in each of the cases: HSPG2::FGFR1, YAP1::FOXR1, ACTB::MAML2, and ARID1B::MAML2. The two cases with neuroendocrine expression occurred as superficial lesions and harbored YAP1::FOXR1 and ARID1B::MAML2 fusions. Our study expands on the molecular spectrum of this enigmatic tumor, further enhancing our current understanding of the disease.

Mixed histiocytic neoplasms: A multicentre series revealing diverse somatic mutations and responses to targeted therapy.

Histiocytic neoplasms are diverse clonal haematopoietic disorders, and clinical disease is mediated by tumorous infiltration as well as uncontrolled systemic inflammation. Individual subtypes include Langerhans cell histiocytosis (LCH), Rosai-Dorfman-Destombes disease (RDD) and Erdheim-Chester disease (ECD), and these have been characterized with respect to clinical phenotypes, driver mutations and treatment paradigms. Less is known about patients with mixed histiocytic neoplasms (MXH), that is two or more coexisting disorders. This international collaboration examined patients with biopsy-proven MXH with respect to component disease subtypes, oncogenic driver mutations and responses to conventional (chemotherapeutic or immunosuppressive) versus targeted (BRAF or MEK inhibitor) therapies. Twenty-seven patients were studied with ECD/LCH (19/27), ECD/RDD (6/27), RDD/LCH (1/27) and ECD/RDD/LCH (1/27). Mutations previously undescribed in MXH were identified, including KRAS, MAP2K2, MAPK3, non-V600-BRAF, RAF1 and a BICD2-BRAF fusion. A repeated-measure generalized estimating equation demonstrated that targeted treatment was statistically significantly (1) more likely to result in a complete response (CR), partial response (PR) or stable disease (SD) (odds ratio [OR]: 17.34, 95% CI: 2.19-137.00, p = 0.007), and (2) less likely to result in progression (OR: 0.08, 95% CI: 0.03-0.23, p < 0.0001). Histiocytic neoplasms represent an entity with underappreciated clinical and molecular diversity, poor responsiveness to conventional therapy and exquisite sensitivity to targeted therapy.

Distinctive genomic features of human T-lymphotropic virus type 1-related adult T-cell leukemia-lymphoma in Western populations.

Adult T-cell leukemia-lymphoma (ATLL) is an aggressive Human T-cell Leukemia Virus Type 1 (HTLV-1)-driven malignancy. Although Western hemisphere (Afro-Caribbean and South American) patients face worse prognoses, our understanding of ATLL molecular drivers derives mostly from Japanese studies. We performed multi-omic analyses to elucidate the genomic landscape of ATLL in Western cohorts. Recurrent deletion and/or damaging mutations involving FOXO3, ANKRD11, DGKZ, and PTPN6 implicate these genes as potential tumor suppressors. RNA-seq, published functional data and in vitro assays support the roles of ANKRD11 and FOXO3 as regulators of T-cell proliferation and apoptosis in ATLL, respectively. Survival data suggest ANKRD11 mutation may confer a worse prognosis. Japanese and Western cohorts, in addition to acute and lymphomatous subtypes, demonstrated distinct molecular patterns. GATA3 deletion was associated with unfavorable chronic cases. IRF4 and CARD11 mutations frequently emerged in relapses after interferon therapy. Our findings reveal novel putative ATLL driver genes and clinically relevant differences between Japanese and Western ATLL patients.

Perifollicular linear projections: A dermatoscopic criterion for the diagnosis of lentigo maligna on the face.

BACKGROUND: Lentigo maligna (LM) can mimic benign, flat, pigmented lesions and can be challenging to diagnose. OBJECTIVE: To describe a new dermatoscopic feature termed "perifollicular linear projections (PLP)" as a diagnostic criterion for LM on the face. METHODS: Retrospective study on reflectance confocal microscopy and dermatoscopy images of flat facial pigmented lesions originating from 2 databases. PLP were defined as short, linear, pigmented projections emanating from hair follicles. Dermatoscopy readers were blinded to the final histopathologic diagnosis. RESULTS: From 83 consecutive LMs, 21/83 (25.3%) displayed "bulging of hair follicles" on reflectance confocal microscopy and 18 of these 21 (85.7%), displayed PLP on dermatoscopy. From a database of 2873 consecutively imaged and biopsied lesions, 252 flat-pigmented facial lesions were included. PLP was seen in 47/76 melanomas (61.8%), compared with 7/176 lesions (3.9%) with other diagnosis (P < .001). The sensitivity was 61.8% (95% CI, 49.9%-72.7%), specificity 96.0% (95% CI, 92.9%-98.4%). PLP was independently associated with LM diagnosis on multivariate analysis (OR 26.1 [95% CI, 9.6%-71.0]). LIMITATIONS: Retrospective study. CONCLUSION: PLP is a newly described dermatoscopic criterion that may add specificity and sensitivity to the early diagnosis of LM located on the face. We postulate that PLP constitutes an intermediary step in the LM progression model.

Superficial Wnt-Activated Melanocytic Nevi/Melanocytomas With a Junctional Component: A Case Series.

ABSTRACT: The conventional morphological characteristics of Wnt-activated deep penetrating/plexiform melanocytomas/nevi (DPN) are those of large spindled or epithelioid melanocytes with distinctive voluminous amphophilic cytoplasm, fine pigmented granules, and surrounding melanophages. The central molecular hallmark is the activation of the Wnt-pathway predominantly driven by mutations in the beta-catenin ( CTNNB1 ) gene. Although typically lacking a junctional component, a lesser-known superficial variant with a junctional component has been identified, which could potentially lead to diagnostic challenges. This study presents a cohort of 11 such cases displaying a junctional component of DPN from 10 patients (5 women and 5 men; age range: 27-78 years; median age: 51 years). The nevi were distributed as follows: 1 conjunctival, 1 scalp, 2 lower limb, and 6 truncal lesions. Eight cases were combined with a conventional nevus, 2 cases displayed pure DPN cytology exhibiting only a junctional element, and 9 cases exhibited some degree of lentiginous architecture. All cases demonstrated a low mitotic index (<1 mitosis/mm 2 ). Immunohistochemistry revealed positive BRAF V600E staining in 8 cases (8/11), whereas all cases tested (11/11) were PRAME negative. Nuclear beta-catenin and LEF1 staining was consistently strong and diffuse with DPN cytology (11/11), along with robust cyclin D1 staining in all cases tested (11/11). By contrast, all 9 conventional nevi showed an absence of nuclear beta-catenin staining (0/9) and weaker, mosaic-type LEF1 and cyclin D1 staining was observed. This study emphasizes the diagnostic challenge these nevi can pose in the absence of a conventional, deeper DPN component, which can potentially be misdiagnosed as melanoma.

Efficacy of immunotherapy with combination of cryotherapy and topical imiquimod for treatment of Kaposi sarcoma.

Multiple treatment modalities for Kaposi sarcoma (KS) have been reported, including chemotherapy, radiation therapy, surgical excision, electrochemotherapy, and cryotherapy. Common topical treatments include timolol, imiquimod, and alitretinoin. We searched our institutional database for patients with ICD-9 or 10 codes for KS seen by a dermatologist with experience in KS management from July 1, 2004 to January 1, 2022. We screened patient charts to include patients who received combination therapy of cryotherapy followed by topical imiquimod three times a week for 2 months (n = 9). Patients were followed in the clinic every 3 months. Time to resolution was assessed by photographic evidence of resolution as determined by a dermatologist and corroborated with clinical documentation in patient charts. Median age (IQR) at KS diagnosis was 58 (27.5) years. All patients were male (n = 9, 100%). Majority were white (n = 7, 78%) and non-Hispanic (n = 8, 89%). Five (56%) had classic KS, one (11%) had HIV-associated KS, and three (33%) were HIV-negative men who have sex with men. Median time to resolution was 30.5 weeks, with a median of two treatments. In our study, 93% (n = 42/45) of lesions and 89% (n = 8/9) of patients experienced complete resolution during a median (range) duration of follow-up of 58 (13-209) weeks. Side effects were limited to pain during cryotherapy, occasional blister formation after cryotherapy, and mild inflammation due to imiquimod. No infections were observed. Combination therapy of cryotherapy and topical imiquimod may be an efficacious and comparatively low-risk treatment for limited, cutaneous KS.

Lentigo maligna melanoma mapping using reflectance confocal microscopy correlates with staged excision: A prospective study.

BACKGROUND: Lentigo maligna/lentigo maligna melanoma (LM/LMM) can present with subclinical extension that may be difficult to define preoperatively and lead to incomplete excision and potential recurrence. Preliminarily studies have used reflectance confocal microscopy (RCM) to assess LM/LMM margins. OBJECTIVE: To evaluate the correlation of LM/LMM subclinical extension defined by RCM compared with the gold standard histopathology. METHODS: Prospective study of LM/LMM patients referred for dermatologic surgery. RCM was performed at the clinically defined initial surgical margin followed by margin-controlled staged excision with paraffin-embedded tissue, and histopathology was correlated with RCM results. RESULTS: Seventy-two patients were included. Mean age was 66.8 years (standard deviation, 11.1; range, 38-89); 69.4% were men. Seventy of 72 lesions (97.2%) were located on the head and neck with mean largest clinical diameter of 1.3 cm (range, 0.3-5). Diagnostic accuracy for detection of residual melanoma in the tumor debulk (after biopsy) had a sensitivity of 96.7% and a specificity of 66.7% when compared with histopathology. RCM margin assessment revealed an overall agreement with final histopathology of 85.9% (κ = 0.71; P < .001). LIMITATIONS: No RCM imaging beyond initial planned margins was performed. CONCLUSION: RCM showed moderate to excellent overall agreement between RCM imaging of LM/LMM and histopathology of staged excision margins.

Acute febrile neutrophilic dermatosis (Sweet syndrome) in acute myeloid leukemia patients: a 28-year institutional experience.

INTRODUCTION: Sweet syndrome (SS) is well-known to be associated with underlying hematologic malignancies. The incidence and qualities of SS among novel targeted therapies for acute myeloid leukemia (AML) have not yet been described. METHODS: Through retrospective review of 19432 patients diagnosed with acute/chronic leukemia or myelodysplastic syndromes/ myeloproliferative neoplasms (MDS+/-MPN) over 28 years, we calculated the incidence of SS in the setting of select hematologic malignancies and described the clinicopathologic characteristics of SS in patients with onset of SS after initiation of novel AML-targeted therapies. RESULTS: Overall incidence of SS was 0.36% (95% CI: 0.27% - 0.45%), which was significantly higher among patients with AML (50/5248, 0.94%; 95% CI: 0.71% - 1.25%). Nine AML patients were on 4 classes of novel targeted treatments - IDH1/2 inhibitor alone, FLT3 inhibitor, IDH2 and DOT1L inhibitor, and anti-CD33 therapy. In therapies inducing myeloid blast differentiation, SS occurred at later onset following treatment. CONCLUSIONS: In AML patients with fever and unusual skin lesions, physicians may consider SS earlier which may shorten time to diagnosis. Future assessments of SS among patients treated with novel therapies for AML and molecular studies of biopsies may help further explain this dermatologic adverse event with earlier diagnosis and management of neutrophilic dermatoses in these patients.

A novel case of cutaneous myxoid spindle cell neoplasm with FMR1-ALK gene fusion and CD34/S100 co-expression.

A novel class of superficial CD34+ and S100+ cutaneous spindle cell neoplasm harboring ALK rearrangements has recently been described. Morphologically, these neoplasms have been characterized by bland spindled cells organized in whorls and cords against myxoid stroma, eventuating in the designation "superficial ALK-rearranged myxoid spindle cell neoplasm." Here, we report a 78-year-old male with a 3-mm pink papule on the chest, clinically concerning for cutaneous carcinoma. Biopsy of the specimen showed a biphasic tumor with hypercellular and hypocellular zones consisting of epithelioid cells and monomorphic, bland spindled cells. The spindled cells were arranged in perineurial-like concentric whorls and cords embedded in a myxo-collagenous stroma. Neoplastic cells were diffusely positive for CD34, S100, and D5F3-ALK, without SOX10 expression. Negative markers included GLUT1, EMA, factor XIIIa, desmin, actin, and SMA. ALK-rearrangement was identified on fluorescence in situ hybridization break-apart assay. A corresponding novel FMR1-ALK fusion was found by next-generation sequencing (NGS) based RNA sequencing. Identification of this new FMR1-ALK fusion signature adds to the spectrum of diagnostic genomic alterations in this newly described class of tumors.

Next-generation sequencing analysis suggests varied multistep mutational pathogenesis for endocrine mucin-producing sweat gland carcinoma with comments on INSM1 and MUC2 suggesting a conjunctival origin.

Endocrine mucin-producing sweat gland carcinoma is a low-grade eyelid tumor. Small biopsies and insensitive immunohistochemistry predispose to misdiagnosis. We aimed to identify clarifying immunohistochemical markers, molecular markers, or both. Clinicopathologic data (22 cases) were reviewed. Immunohistochemistry (insulinoma-associated protein 1, BCL-2, mucin 2 [MUC2], mucin 4, androgen receptor, ß-catenin, and Merkel cell polyomavirus) and next-generation sequencing (Memorial Sloan Kettering integrated mutation profiling of actionable cancer targets, 468 genes) were performed (3 cases). Female patients (n = 15) and male patients (n = 7) (mean age 71.8 years; range 53-88 years) had eyelid or periorbital tumors (>90%) with mucin-containing solid or cystic neuroendocrine pathology. Immunohistochemistry (insulinoma-associated protein 1, BCL2, androgen receptor, retinoblastoma-associated protein 1, and ß-catenin) was diffusely positive (5/5), MUC2 partial, mucin 4 focal, and Merkel cell polyomavirus negative. Memorial Sloan Kettering integrated mutation profiling of actionable cancer targets identified 12 single-nucleotide variants and 1 in-frame deletion in 3 cases, each with DNA damage response or repair (BRD4, PPP4R2, and RTEL1) and tumor-suppressor pathway (BRD4, TP53, TSC1, and LATS2) mutations. Microsatellite instability, copy number alterations, and structural alterations were absent. Insulinoma-associated protein 1 and MUC2 are positive in endocrine mucin-producing sweat gland carcinoma. MUC2 positivity suggests conjunctival origin. Multistep pathogenesis involving DNA damage repair and tumor-suppressor pathways may be implicated.

Primary cutaneous T-cell lymphomas other than mycosis fungoides and Sézary syndrome. Part II: Prognosis and management.

Primary cutaneous T-cell lymphomas (CTCLs) other than mycosis fungoides (MF) and Sézary syndrome (SS) encompass a heterogenous group of non-Hodgkin lymphomas with variable clinical courses, prognoses, and management approaches. Given the morphologic and histologic overlap among the CTCL subtypes and other T-cell lymphomas with cutaneous manifestations, thorough evaluation with clinicopathologic correlation and exclusion of systemic involvement are essential prior to initiating therapy. Staging and treatment recommendations vary, depending on the subtype, clinical behavior, and treatment response. Generally, for subtypes in which staging is recommended, Ann Arbor or tumor, node, metastasis staging specific to CTCL other than MF or SS are used. For many subtypes, there is no standard treatment to date. Available recommended treatments range widely, from no active or minimal intervention with skin-directed therapy to aggressive systemic therapies that include multi-agent chemotherapy with consideration for hematopoietic stem cell transplant. Emerging targeted therapies, such as brentuximab, a chimeric antibody targeting CD30, show promise in altering the disease course of non-MF/SS CTCLs.

Primary cutaneous T-cell lymphomas other than mycosis fungoides and Sézary syndrome. Part I: Clinical and histologic features and diagnosis.

Primary cutaneous T-cell lymphomas (CTCLs) are defined as lymphomas with a T-cell phenotype that present in the skin without evidence of systemic or extracutaneous disease at initial presentation. CTCLs other than mycosis fungoides and Sézary syndrome (SS) account for approximately one third of CTCLs and encompass a heterogenous group of non-Hodgkin lymphomas, ranging from indolent lymphoproliferative disorders to aggressive malignancies with a poor prognosis. The spectrum of CTCLs continues to broaden as new provisional entities are classified. Given the morphologic and histologic overlap among CTCLs and other diagnoses, a thorough clinical history, physical evaluation, and clinicopathologic correlation are essential in the work up and diagnosis of these rare entities. This article will summarize the epidemiologic, clinical, pathologic, and diagnostic features of CTCLs other than mycosis fungoides and SS.

Secondary skin involvement in classic Hodgkin lymphoma: Results of an international collaborative cutaneous lymphoma working group study of 25 patients.

BACKGROUND: Cutaneous involvement by classic Hodgkin lymphoma (CHL) is an extraordinarily rare phenomenon in the current era. To date, no single large case series of cutaneous involvement by Hodgkin lymphoma has ever been reported in the literature. METHODS: A comprehensive search for cases designated "skin" and "Hodgkin" was performed at different institutions between 1990 and 2020. Twenty-five cases were identified, and each case was independently reviewed by at least three board-certified dermatopathologists and/or hematopathologists. RESULTS: All cases represented examples of systemic CHL with secondary skin dissemination. A single lesion, usually a tumor, nodule or infiltrative plaque was observed in 56% of cases and multiple lesions were present in 28% of cases. Most patients (86%-12/14) had a diagnosis of stage IV disease at first diagnosis. The interval between the clinical (first) diagnosis of HL and the development of skin lesions ranged between 6 and 108 months (average 33.75 months). Comprehensive histopathologic evaluation of these cases (at the initial diagnosis) revealed a diagnosis of classic HL not otherwise specified (NOS) in 60% of cases (15/25), nodular sclerosis type in 24% (6/25), mixed cellularity in 12% (3/25), and lymphocyte depleted in 4% (1/25). CONCLUSIONS: We provide documentation of a large series of CHL with secondary skin involvement in association with CHL with additional clinical, morphologic, and immunophenotypic features.

Treatment of Extramammary Paget Disease and the Role of Reflectance Confocal Microscopy: A Prospective Study.

BACKGROUND: Extramammary Paget disease (EMPD) poses treatment challenges. Invasive and noninvasive treatment modalities exist with variable success reported. Reflectance confocal microscopy (RCM) is emerging as an adjuvant diagnostic tool. OBJECTIVE: To evaluate the treatment of EMPD patients and the role of RCM. METHODS: Prospective study. Demographic and tumor characteristics were recorded. Handheld-RCM was performed and correlated with histology. Treatment, clearance, pathology, and follow-up were all recorded. RESULTS: Thirty-six EMPD lesions in 33 patients were included. Mean age was 71.7 years, and 23 were men. Mean number of surgical stages needed to clear margins was 1.9 (SD, 0.9; 1.0-3.0 stages), and mean margin needed to clear was 1.8 cm. Reflectance confocal microscopy correlated well with scouting punch biopsies (kappa, 0.93; p < .001). Disruption of the dermoepidermal junction was associated with invasive EMPD versus in situ (83.3% vs 25.9%) on histology (p = .01). LIMITATIONS: Relatively small sample size. CONCLUSION: Extramammary Paget disease is challenging, and lesion demarcation is of the utmost importance. Using a staged surgical excision approach, the mean margins needed were 1.8 cm, less than previously reported. Nonsurgical modalities, including radiation therapy, imiquimod, or photodynamic therapy can be considered if surgery is not pursued. Reflectance confocal microscopy is a valuable noninvasive imaging modality for the management of EMPD.

C-C chemokine receptor 4 expression in CD8+ cutaneous T-cell lymphomas and lymphoproliferative disorders, and its implications for diagnosis and treatment.

AIMS: Patients with aggressive CD8+ cutaneous T-cell lymphomas (CTCLs) progress rapidly and respond poorly to therapy. Confounding treatment planning, there is clinicopathological overlap between aggressive CD8+ CTCLs and other lymphoproliferative disorders (LPDs). Hence, improved diagnostic methods and therapeutic options are needed. The aim of this study was to examine C-C chemokine receptor 4 (CCR4) expression as a diagnostic and therapeutic biomarker in CD8+ CTCLs/LPDs. METHODS AND RESULTS: Forty-nine cases (41 patients) with CD8+ CTCLs/LPDs were examined, including CD8+ mycosis fungoides (MF) (n = 14), aggressive epidermotropic CD8+ cytotoxic T-cell lymphoma (AETCL) (n = 8), subcutaneous panniculitis-like T-cell lymphoma (SPTCL) (n = 7), CD30+ LPDs (n = 6), primary cutaneous γδ T-cell lymphoma (GDTCL) (n = 6), and others (n = 8). Immunohistochemical tissue staining was performed with a CCR4 monoclonal antibody on formalin-fixed paraffin-embedded tissue sections. CCR4 immunostaining was graded as percentage infiltrate, i.e. high (>25%) and low (≤25%), and the results were correlated with clinicopathological diagnoses. CCR4 expression was seen in 69% of the studied cases. Any CCR4 positivity was seen in all CD8+ MF cases, in 83% of CD30+ LPD cases, in 75% of AETCL cases, in 33% of GDTCL cases, and in none of the SPTCL cases. High CCR4 expression was seen in 79% of CD8+ MF cases versus 33% of CD30+ LPD cases, in 17% of GDTCL cases, and in 12.5% of AETCL cases. Patients with more advanced MF stage had higher CCR4 expression. CONCLUSIONS: CCR4 immunohistochemistry may be an adjunct in distinguishing advanced CD8+ MF from other CD8+ CTCLs/LPDs. Although CCR4 expression may justify therapeutic targeting of this receptor in CD8+ MF, the role of such therapies in other CD8+ CTCLs/LPDs is not yet clear.

Outcomes and prognostic factors in African American and black patients with mycosis fungoides/Sézary syndrome: Retrospective analysis of 157 patients from a referral cancer center.

BACKGROUND: The prevalence of mycosis fungoides/Sézary syndrome (MF/SS) is higher in the black population than in the white population in the United States and worse outcomes have been observed in black patients. OBJECTIVE: To describe the outcomes and to identify prognostic factors in African American and black patients with MF/SS. METHODS: Clinical features and follow-up data were analyzed in 157 self-identified African American or black patients seen during 1994-2018. RESULTS: We included 122 patients with early stage MF and 35 patients with advanced-stage disease (median follow-up of 25 months). Overall, >80% of the patients who died from disease or progressed had erythema or hyperpigmentation without hypopigmentation. Patients with hypopigmentation, either as the sole manifestation or in combination with other lesions, had better overall survival (P = .002) and progression-free survival (P = .014). Clinical stage, TNMB classification, plaque disease, and elevated serum lactate dehydrogenase were also significantly associated with outcomes. Demographic and socioeconomic parameters were not associated with prognosis. LIMITATIONS: A retrospective study at a single cancer center. CONCLUSION: MF/SS manifestations and outcomes in African American and black patients are heterogeneous. Demographic and socioeconomic factors do not seem to have a prognostic role, while clinical characteristics might help in the stratification of risk of progression and shorter survival, allowing for individually tailored therapeutic interventions.

Drugs as a Frequent Cause of Acute Rash in Patients after CD34+-Selected Peripheral Blood Stem Cell Transplantation.

Although histopathological differences have been reported between acute graft-versus-host disease (aGVHD) rash and non-aGVHD rash in CD34+-selected peripheral blood stem cell transplantation (PBSCT) recipients, skin biopsy alone is usually insufficient to determine rash etiology. As such, distinguishing inflammatory non-aGVHD rashes, such as drug eruptions, from cutaneous aGVHD after CD34+-selected PBSCT remains challenging and relies on clinical presentation. This study aimed to identify etiologies of skin rash in the first year after CD34+-selected PBSCT and to assess whether laboratory serologic markers, transplant characteristics, and rash morphology and symptomatology aid in differentiation of cutaneous aGVHD rash versus non-aGVHD rash. We conducted a retrospective study of 243 adult patients who underwent CD34+-selected PBSCT at Memorial Sloan Kettering Cancer Center between 2008 and 2011. Among this cohort of transplant recipients, only 43 patients (17.7%) developed cutaneous aGVHD. A total of 152 patients (63%) were identified with rash within 1 year after PBSCT. The proportion of patients who experienced peripheral eosinophilia was not different between those with an aGVHD versus non-aGVHD rash (P ≥ .90), nor when stratified by CD34+ selection method (Isolex, P = .70; CliniMACS, P≥ .90). The proportion of patients with pruritus was also not different between those with an aGVHD rash versus non-aGVHD rash (P= .20), or when stratified by CD34+ selection modality (Isolex, P = .20; CliniMACS, P = .50). The most common cause of non-aGVHD rash among those with a clear etiology was drug (39% of Isolex; 26% of CliniMACS). Single drug culprits were identified in 51% of drug rashes. The most commonly reported offending agents included antibiotics, keratinocyte growth factor, chemotherapy, and recombinant glycosylated human IL-7.

Follicular mucinosis in patients with hematologic malignancies other than mycosis fungoides: A clinicopathologic study.

BACKGROUND: Follicular mucinosis (FM), which is defined by mucin accumulation within follicular epithelium, may occur in mycosis fungoides (MF). FM without MF is occasionally reported in systemic hematologic malignancies and may be diagnostically challenging. OBJECTIVE: To describe clinicopathologic characteristics of FM in patients with hematologic malignancies other than MF. METHODS: Clinical data and histopathology features were analyzed in patients with FM and hematologic malignancies diagnosed between 1994 and 2017. RESULTS: A total of 18 patients with FM and systemic hematologic malignancies without cutaneous T-cell lymphoma (CTCL) were identified; 9 of them were discovered after hematopoietic stem cell transplantation. No patients with non-CTCL-associated FM (n = 46 [37 biopsy specimens]) developed CTCL during a mean follow-up of 4.3 years. Of the cases of CTCL associated with FM (n = 44 [31 biopsy specimens]), MF was the most common subtype (n = 38), although other CTCLs were identified. FM in patients with non-CTCL hematologic malignancies differed clinically from those with MF-associated FM, presenting most frequently with erythematous papules (P < .0001), without plaques (P <.0001), without alopecia (P = .001), and without histopathologically identified epidermal exocytosis (P = .013). LIMITATIONS: A retrospective study in a single cancer center. CONCLUSIONS: FM can present in systemic hematologic malignancies, including after hematopoietic stem cell transplantation. Papular lesional morphologic and histopathologic features may help to distinguish these cases from MF.