Spiny Keratoderma: Clinical and Histopathological Findings in a Series of 3 Cases.

ABSTRACT: Spiny keratoderma is a rare entity presenting with minute keratotic spines on the palms and soles. Spiny keratoderma can be inherited or acquired, and the acquired form may be associated with underlying malignancy or systemic disease. Clinically, the differential diagnosis includes other digitate keratoses on acral sites, most notably arsenical keratosis, filiform verruca, and punctate porokeratosis. Biopsy findings typically include a column of parakeratosis overlying a diminished granular cell layer. In this article, we present 3 cases of acquired spiny keratoderma in patients with various systemic diseases, but no underlying malignancy.

IRF8 may be a useful marker for blastic plasmacytoid dendritic cell neoplasm, especially with weak CD123 expression.

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.

PRAME immunohistochemistry can distinguish melanocytic pseudonests of lichenoid reactions from melanoma in situ.

BACKGROUND: Distinguishing melanocytic pseudonests encountered in lichenoid dermatoses or lichenoid keratoses from melanoma in situ (MIS) with brisk lichenoid inflammation can prove challenging. METHODS: We designed a case-control study to evaluate the accuracy metrics of PRAME immunohistochemistry to distinguish melanocytic pseudonests in lichenoid dermatoses or keratoses from inflamed MIS. Immunostaining for PRAME was performed on paraffin-embedded formalin-fixed diagnostic tissue using a rabbit monoclonal antibody to PRAME (Abcam), with a 1:3200 dilution on a Leica Bond detection system. RESULTS: Our search identified 21 cases of melanocytic pseudonests (n = 21, 46%) encountered in lichenoid dermatoses and 24 cases of inflamed MIS (n = 24, 53%). Each method of evaluating PRAME immunohistochemistry (PRAME+ clusters, PRAME % of melanocytes by four categories and PRAME+ melanocyte counts per linear mm of epidermal basal layer) showed statistically significant differences between the MIS and the pseudonest cohorts (respectively, p < 0.001; p < 0.001; and p < 0.001). Receiver operating characteristics analysis for PRAME+ melanocyte counts per linear mm of epidermal basal layer revealed an area under the curve of 0.9 ± 0.05 (95% confidence interval 0.9-1.0). When determining an optimal cut-off point for the best Youden index [sensitivity (%) + specificity (%) - 100], the cut-off of 1.0 PRAME+ melanocytes per linear mm showed a sensitivity of 79.2% and specificity of 85.7% (Youden index 0.65) to distinguish MIS from pseudonests. CONCLUSION: PRAME immunohistochemistry may constitute an additional tool for this challenging differential diagnosis.

Recent Advances in the Classification of Gynecological Tract Tumors: Updates From the 5th Edition of the World Health Organization "Blue Book".

CONTEXT.­: The World Health Organization Classification of Tumours: Female Genital Tract Tumors, 5th edition, published in September 2020, comes 6 years after the 4th edition, and reflects the monumental leaps made in knowledge about the biology of gynecological tumors. Major changes include revised criteria for the assignment of the site of origin of ovarian and fallopian tube tumors, a revision in the classification of squamous and glandular lesions of the lower genital tract based on human papillomavirus association, and an entire chapter devoted to genetic tumor syndromes. This article highlights the changes in the 5th edition relative to the 4th edition, with a focus on areas of value to routine clinical practice. OBJECTIVE.­: To provide a comprehensive update on the World Health Organization classification of gynecological tumors, highlighting in particular updated diagnostic criteria and terminology. DATA SOURCES.­: The 4th and 5th editions of the World Health Organization Classification of Tumours. CONCLUSIONS.­: The World Health Organization has made several changes in the 5th edition of the update on female genital tumors. Awareness of the changes is needed for pathologists' translation into contemporary practice.

Microsecretory adenocarcinoma: Cutaneous counterpart of a newly described salivary gland tumor with recurrent MEF2C::SS18 fusion.

Microsecretory adenocarcinoma (MSA) is a distinctive low-grade salivary gland tumor with a novel MEF2C::SS18 fusion. Although MSA most commonly occurs in the oral cavity, cases of MSA involving skin have been described recently. Histopathologically, MSA is characterized by microcystic tubules with basophilic luminal secretions, a fibromyxoid stroma and cells with eosinophilic or clear cytoplasm, and a unique immunohistochemical profile (S100+, SOX10+, p63+, and p40-). Cutaneous MSA may rarely demonstrate high-grade features. Follow-up studies have shown MSA to be an indolent tumor, without local recurrence or metastasis after complete surgical excision in the vast majority of cases. It is important to recognize the histopathological features of this unique tumor with a novel MEF2C::SS18 fusion that may occur in skin and to utilize appropriate molecular studies for accurate diagnosis.

Erratum: Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation.

[This corrects the article DOI: 10.1016/j.xhgg.2021.100028.].

Global assessment of IRF8 as a novel cancer biomarker.

Interferon regulatory factor 8 (IRF8) is a member of the IRF family that is specific to the hematopoietic cell and is involved in regulating the development of human monocytic and dendritic-lineage cells, as well as B-cells. Because its utility as a sensitive and specific monoblast marker in the context of acute monocytic leukemias has been recently demonstrated, we hypothesized that it may also be useful as a novel immunohistochemical marker in myeloid sarcomas and blastic plasmacytoid dendritic cell neoplasms (BPDCNs) with respect to their differential diagnoses. In this retrospective study, we analyzed the IHC expression pattern of IRF8 in 385 patient samples across 30 types of cancers, referenced to their mRNA expression data available through The Cancer Genome Atlas. In addition, we assessed IRF8 in 35 myeloid sarcomas and 15 BPDCNs. Twenty-four of 35 cases of myeloid sarcomas (68.5%) showed positivity for IRF8, with six cases (17.1%) demonstrating IRF8 expression in the absence of CD34 and MPO. All 15 of 15 BPDCNs (100%) showed strong uniform expression of IRF8 and were occasionally more definitive than CD123. IRF8 was negative in all desmoplastic small round cell tumors, Ewing sarcomas, synovial sarcomas, and undifferentiated pleomorphic sarcomas, as well as all epithelial malignancies tested except for 2 triple negative breast cancers that showed subset weak staining. In conclusion, IRF8 is a novel marker helpful in identifying extranodal hematopoietic tumors that can otherwise be difficult to diagnose given the broad differential diagnoses and frequent loss of more common lineage-defining markers.

Cytokine RNA In Situ Hybridization Permits Individualized Molecular Phenotyping in Biopsies of Psoriasis and Atopic Dermatitis.

Detection of individual cytokines in routine biopsies from patients with inflammatory skin diseases has the potential to personalize diagnosis and treatment selection, but this approach has been limited by technical feasibility. We evaluate whether a chromogen-based RNA in situ hybridization approach can be used to detect druggable cytokines in psoriasis and atopic dermatitis. A series of psoriasis (n = 20) and atopic dermatitis (n = 26) biopsies were stained using RNA in situ hybridization for IL4, IL12B (IL-12/23 p40), IL13, IL17A, IL17F, IL22, IL23A (IL-23 p19), IL31, and TNF (TNF-α). NOS2 and IFNG, canonical psoriasis biomarkers, were also included. All 20 of the psoriasis cases were positive for IL17A, which tended to be the predominant cytokine, although some cases had relatively higher levels of IL12B, IL17F, or IL23A. The majority of cytokine expression in psoriasis was epidermal. A total of 22 of 26 atopic dermatitis cases were positive for IL13, also at varying levels; a subset of cases had significant IL4, IL22, or IL31 expression. Patterns were validated in independent bulk RNA-sequencing and single-cell RNA-sequencing datasets. Overall, RNA in situ hybridization for cytokines appears highly specific with virtually no background staining and may allow for individualized evaluation of treatment-relevant cytokine targets in biopsies from patients with inflammatory skin disorders.

Epidermotropic metastasis of squamous cell carcinoma of the tonsil: A case report with molecular confirmation.

Metastasis of oropharyngeal squamous cell carcinoma (SCC) to skin is uncommon and portends a poor prognosis. Clinical history and histopathology are key to discerning between metastatic disease vs de novo SCC of the skin. We describe a case of an HPV+ tonsillar SCC in a 77-year-old male, with metastasis to the neck skin. This case is unique because of prominent in situ epidermal involvement on skin biopsy specimen, complicating the distinction between primary and secondary disease. The nature of the lesion was resolved using next-generation sequencing of both the primary oropharyngeal SCC and skin lesion biopsy specimens. Both tumors showed identical ATR D1639G somatic mutations, while the skin lesion contained an additional POLE F1366L mutation. Clonal evolution of metastatic lesions is a well-described phenomenon; comparing the genetic profiles of primary and metastatic specimens can be useful in evaluating the tumor origin as well as identifying targetable genetic aberrations.

Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation.

The term "cavernous hemangioma" has been used to describe vascular anomalies with histology featuring dilated vascular spaces, vessel walls consisting mainly of fibrous stromal bands lined by a layer of flattened endothelial cells, and an irregular outer rim of interrupted smooth muscle cells. Hepatic hemangiomas (HHs) and cutaneous venous malformations (VMs) share this histologic pattern, and we examined lesions in both tissues to identify genetic drivers. Paired whole-exome sequencing (WES) of lesional tissue and normal liver in HH subjects revealed a recurrent GJA4 c.121G>T (p.Gly41Cys) somatic mutation in four of five unrelated individuals, and targeted sequencing in paired tissue from 9 additional HH individuals identified the same mutation in 8. In cutaneous lesions, paired targeted sequencing in 5 VMs and normal epidermis found the same GJA4 c.121G>T (p.Gly41Cys) somatic mutation in three. GJA4 encodes gap junction protein alpha 4, also called connexin 37 (Cx37), and the p.Gly41Cys mutation falls within the first transmembrane domain at a residue highly conserved among vertebrates. We interrogated the impact of the Cx37 mutant via lentiviral transduction of primary human endothelial cells. We found that the mutant induced changes in cell morphology and activated serum/glucocorticoid-regulated kinase 1 (SGK1), a serine/threonine kinase known to regulate cell proliferation and apoptosis, via non-canonical activation. Treatment with spironolactone, an inhibitor of angiogenesis, suppressed mutant SGK1 activation and reversed changes in cell morphology. These findings identify a recurrent somatic GJA4 c.121G>T mutation as a driver of hepatic and cutaneous VMs, revealing a new pathway for vascular anomalies, with spironolactone a potential pathogenesis-based therapy.

Dermatofibrosarcoma protuberans in pregnancy: a case series and review of the literature.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous sarcoma, which has been reported in pregnancy. This case series reports the clinical and histopathological findings of DFSP in pregnancy. METHODS: Eighteen cases of DFSP, including six unreported cases and 12 cases from the literature, were identified. Age, anatomic location, tumor size, changes in tumor characteristics during pregnancy, histopathological features, and treatment were recorded. Follow-up data, when available, were noted. RESULTS: The average age of the cohort was 30.6 years (range 19-38). Ten tumors (55.6%) were located on the trunk, four (22.2%) on the head and neck, three (16.7%) on the extremities, and one (5.6%) in the genitalia. Most tumors demonstrated features of conventional DFSP (12/18, 66.7%), while the remaining were identified as DFSP with fibrosarcomatous (FS) change (3/18, 16.7%), atrophic DFSP (2/18, 11.1%), and myxoid DFSP (1/18, 5.6%). Treatment was reported in 17 cases, at least nine of which were treated postpartum. Ten patients were treated with excision, while seven underwent Mohs micrographic surgery. Three patients recurred on follow-up, one with local recurrence and two with distant metastasis. CONCLUSIONS: DFSP can undergo enlargement or change in size or color in pregnancy, possibly mediated by hormones. While the majority of cases in this series represented conventional DFSP, unusual clinical and histopathological variants were also present. Treatment in most cases can be safely delayed until after delivery, but recurrent or very large tumors may require treatment prepartum. Close monitoring for recurrence or metastasis is advised.

Prelamination of Vascularized Tensor Fascia Lata for Complex Abdominal Wall Reconstruction.

ABSTRACT: There are 2 to 5 million laparotomies performed in the United States annually. Of these, 250,000 to 350,000 will undergo a ventral hernia repair. Repairs are often complicated by recurrence and infection. These risks are significantly increased in previously infected repairs, with reported recurrence rates varying from 17% to 28% after repair of infected ventral hernias, double the rates reported for first-time uninfected repairs. We describe here a novel treatment strategy involving the creation then use of bilateral prelaminated permanent mesh-reinforced tensor fascia latae flaps for abdominal wall reconstruction in patients who have recurrent ventral hernias and had undergone previous repairs complicated by infection. Previous repairs included anterior components separation, thereby making subsequent fascial release techniques and achievement of a reinforced repair extremely unlikely. Three patients were treated by a single surgeon using this 2-stage technique. There have been no incidences of recurrence and no infections after 2 to 10 years. In these patients, the only conventional option would have been a bridged repair with absorbable mesh. Combining the advantages of permanent mesh and well-vascularized autologous tissue optimizes the repair's tensile strength while mitigating the chance of recurrent infection associated with the use of permanent mesh. We propose that this strategy may be an appropriate treatment option for patients with recurrent ventral hernias that have not responded to other conventional modalities of treatment.

Cervical Pemphigus Vulgaris Presenting as Postmenopausal Bleeding.

Pemphigus vulgaris is a severe mucocutaneous blistering disease with rare genital involvement. When present, female genital involvement is typically vulvo-vaginal and associated with characteristic bullous lesions elsewhere, most commonly in the oral cavity. Postmenopausal bleeding as a symptom of pemphigus is not reported to date. We present 2 cases of pemphigus vulgaris with postmenopausal bleeding that led to significant work-up for the patients, including hysterectomy for 1 patient. The site of bleeding was established to be related to cervical involvement in 1 patient and assumed to be of cervical origin in the other. As improving treatment modalities result in long-term survival in patients with pemphigus, isolated genital relapse/recurrence of pemphigus vulgaris involving the cervix may result with symptoms not previously attributed to the disease including postmenopausal bleeding. Both gynecologists and pathologists need to be aware of this possibility to accurately label symptoms as disease related and avoid unnecessary interventions for patients.