Is it Possible to Obtain Immunofluorescence Data in Formalin-Fixed Paraffin-Embedded Skin Samples for the Diagnosis of Pemphigus Vulgaris and Bullous Pemphigoid.

OBJECTIVE: The gold-standard method for assessment of autoimmune bullous disease is direct/indirect immunofluorescence (IF) examination applied to fresh frozen tissue. Since the sensitivity of IF is greatly reduced in formalin-fixed paraffin-embedded (FFPE) tissues, IF cannot be relied upon in these samples. However, immunohistochemistry with the C4d antibody is a promising marker used as a surrogate for immune complex deposition, in nephropathology practice, and the paraffin IF method is also used as a `salvage` technique when fresh frozen tissue is not available or lacks glomeruli. We aimed to investigate whether it is possible to obtain immunofluorescence data from FFPE tissues diagnosed with bullous pemphigoid (BP) and pemphigus vulgaris (PV) and its relationship with inflammatory parameters in the skin. MATERIAL AND METHODS: Eighty-nine in-house cases with both IgG and C3 positivity by routine immunofluorescence examination were included in the study. Inflammation parameters were evaluated in hematoxylin-eosin sections. Immunofluorescence study with IgG protease digestion and C4d immunohistochemistry were performed. RESULTS: Results of 83 biopsies were obtained by paraffin immunofluorescence with IgG. There were positive reactions in 28 (34%) of these 83 biopsies. Five of the 28 positive results belonged to BP (18%), and 23 were PV (82%). Ten positive results were on lesional skin (36%), and 18 (64%) were on non-lesional skin. In the immunohistochemical study with C4d, 84 biopsy results were obtained. There were positive reactions in 34 (40.4%) of 84 biopsies. Of the 34 positive results, 12 belonged to BP (35.3%) and 22 to PV (64.7%). Again, 22 (64.7%) of 34 positive results belonged to lesional skin, and 12 (35.3%) belonged to non-lesional skin. When both techniques were used together, 44 (54%) of 81 biopsies yielded positive results for at least one of the two studies, while in 37 (46%), both tests showed negative results. CONCLUSION: The sensitivity of both IgG and C4d was less than in the literature, especially in BP-diagnosed biopsies. Positive samples were mostly PV. In conclusion, obtaining immunofluorescence data in FFPE samples is possible and is independent of the related skin being lesional or not, however, negative results should not be relied upon.

Phenotypic and Genetic Features that Differ Between Hereditary and Sporadic Melanoma: Results of a Preliminary Study from a Single Center from Turkey.

INTRODUCTION: Most melanoma patients under our supervision lack characteristic phenotypic features for melanoma. In contrast, history of cancers other than melanoma and early age at onset were common. This observation was in favor of hereditary melanoma. OBJECTIVES: To search for the phenotypic and genetic features that differ between sporadic and hereditary melanomas. METHODS: In order to reveal phenotypic features, detailed physical exam was conducted to all melanoma patients (N = 43) and for genetic features. CDKN2A and MC1R mutations were detected with Sanger sequencing method. Assignment to hereditary and sporadic groups was done according to the "melanoma cancer syndrome assessment tool". Patients who were diagnosed before the age of 50 were also assigned to the hereditary melanoma group. RESULTS: Thirty-one patients were assigned to the hereditary group and 12 to the sporadic group. Fair eye color was statistically significantly higher in the sporadic group (P = 0.000). CDKN2A was detected in only 1 patient in the hereditary group. MC1R mutations were found in 12 out of 13 (92.3%) in the hereditary group with a score =3 points, 13 out of 18 (72.2%) in the early age at onset group and 5 out of 12 (41.7%) in the sporadic group (P = 0.024). CONCLUSIONS: Incidence of CDKN2A mutations in our hereditary group is in accordance with the reported incidences from Mediterranean countries. The difference between the hereditary and sporadic groups in terms of MC1R mutations supports the idea that MC1R genetic testing might help to determine patients with higher risk for hereditary melanoma.

A rare involvement in skin cancer: Merkel cell carcinoma with bone marrow infiltration in a kidney transplant recipient.

A 60-year-old man presented with a painless, rapidly growing, haemorrhagic pink nodule on the posterior of his thigh that had developed 1 month previously. He had a diagnosis of IgA nephropathy and had received a renal allograft 7 years before. An excisional biopsy was performed and the diagnosis of Merkel cell carcinoma (MCC) was made. No distant metastases was detected. 10 months after first presentation, due to the development of acute pancytopenia and concomitant FDG PET/CT findings compatible with disease progression, bone marrow biopsy was performed which revealed metastasis of MCC. Dermatologists and oncologists should be aware that MCC could potentially involve the bone marrow in organ transplant recipients. In the follow-up period, a complete blood count should be carried out; FDG PET/CT can be obtained to follow up the metabolic status of the disease and bone marrow biopsy should be performed if necessary.

The role of NLRP1 and NLRP3 inflammasomes in the etiopathogeneses of pityriasis lichenoides chronica and mycosis fungoides: an immunohistochemical study.

Mycosis fungoides (MF) is the most common subtype of primary cutaneous T cell lymphomas, whereas pityriasis lichenoides chronica (PLC) is a chronic inflammatory skin disorder. The inflammasome is a part of the natural immune system which has a multimeric structure consisting of the receptor, adaptor and effector protein that show specificity for various ligands or activators. After the activation of the inflammasome complex, caspase 1 becomes activated which subsequently triggers interleukin-18 (IL-18) and interleukin-1ß (IL-1ß) production. In our study we aimed to examine the roles of nucleotide-binding oligomerization domain-like receptor containing pyrin domain 1 (NLRP1) and nucleotide-binding oligomerization domain-like receptor containing pyrin domain (NLRP3) inflammasomes in the etiopathogeneses of PLC and MF. NLRP1, NLRP3, caspase 1, IL-18 and IL-1ß levels were examined and compared immunohistochemically in the skin biopsies belonging to 16 control patients; 16 PLC cases, 12 cases with stage 1 MF and 12 cases with other stages of MF (stage 2-4). In the paired comparisons of NLRP1, stage 2-4 MF group and PLC group were shown to have increased levels of NLRP1 expression compared to the control group. IL-1ß was also expressed at statistically significantly higher levels in each of the stage 1 MF, stage 2-4 MF and PLC groups compared to the control group. In the paired comparisons of caspase 1 and IL-18, it was found that stage 1 MF, stage 2-4 MF and PLC groups had increased levels of expression compared to the control group. Our findings suggest that the NLRP1 inflammasome pathway might play a role in the etiopathogenesis and progression of PLC and MF.

Diagnostic Role of Direct Immunofluorescence Assay in Determining The Etiology of Erythroderma: Experience in a Tertiary Referral Hospital.

Introduction: Erythroderma is a life-threatening dermatologic emergency which is characterized by diffuse erythema and exfoliation affecting more than 90% of the body surface area. Most common cutaneous diseases associated with erythroderma are systemic contact dermatitis, psoriasis, drug eruption and atopic dermatitis. Clinical-pathological correlation is used to determine the underlying disease. In addition, direct immunofluorescence (DIF) may provide significant clues for etiology of erythroderma especially in the case of autoimmune bullous skin diseases (ABSDs). Objectives: In our study, we aimed to analyze the demographic data, clinical pre-diagnoses, final diagnosis, histopathological and DIF examination findings, accompanying systemic signs and laboratory abnormalities of erythrodermic patients. Methods: We conducted a retrospective study of 31 erythroderma patients in a referral hospital between 2014 and 2021. Cutaneous biopsies were taken from all patients for H&E and DIF examination. Results: Average age was 54.6 ± 23 years, 48.4% of the patients were female (N = 15) whereas 51.6 % of the patients were male (N = 16). Average time between the onset of rash and biopsy was 18.8 days. DIF analysis showed immune deposits in 19.4% (N = 6) of the patients; whereas no immune deposits were detected in 80.6% (N = 25) of the patients. The most frequent final diagnosis was adverse cutaneous drug eruption followed by ABSDs. Conclusions: Our findings suggest that DIF may be used in conjunction with clinical-pathologic and clinical findings to reveal the associated skin diseases in erythrodermic patients. Erythrodermic patients presenting with clinical findings of ABSD should be considered for DIF examination.

Merkel cell number and distribution, and CD200 expression in patients with lichen planopilaris and discoid lupus erythematosus.

BACKGROUND: Immune mechanisms are considered to be responsible for the pathogenesis of cicatricial alopecia in lichen planopilaris (LPP) and discoid lupus erythematosus (DLE) diseases. CD200 has an immunomodulatory function in hair follicles. The functions of Merkel cells (MCs) in hair follicles remain to be fully understood. OBJECTIVE: This study aimed to determine the number and distribution of MCs as well as CD200 expression in patients with DLE and LPP. METHODS: Using immunohistochemistry, the number and distribution of MCs (staining with CK20) and CD200 expression in biopsy specimens of LPP and DLE patients were compared with control group patients. RESULTS: The number of follicular MCs, total MCs, mean follicular MCs, and CD200 expression were significantly lower in the case groups compared to the control group. In CD200- cases, the number of follicular MCs and mean follicular MCs were significantly lower than in CD200+ cases. Retrospective design, lack of data regarding the history of alopecia in the control group, and unknown stage of disease in patients were the limitations. CONCLUSION: MC loss might play a role in immune privilege collapse in hair follicles. This study is novel in terms of investigating MCs in DLE and LPP patients.

The correlation between tumor thickness and aggressive histopathological pattern in Basal cell carcinoma.

BACKGROUND: The significance of tumor thickness is not clear in the prognosis of basal cell carcinoma. We aimed to identify the relationship between the tumor thickness and aggressive histopathological growth pattern in BCC. METHODS: We retrospectively reviewed 85 primary BCCs of 82 patients. A total of 78 (91.7%) tumor slides were available for review, 7 (8.2%) missing slides in archive could not to be re-evaluated. We recorded the histological subtype, ulceration, perineural invasion, and the tumor thickness. Tumors with infiltrative, micronodular, morpheaform and basosquamous features were classified as having an aggressive growth pattern. RESULTS: The aggressive growth pattern was determined in 21 (26.9%) tumors with a mean tumor thickness of 2.19 ± 0.71 mm (range, 0.9-3.40). The non-aggressive growth pattern was detected in 57 (73%) tumors and the mean tumor thickness was 1.76 ± 0.87 mm (range 0.50-4.40 mm). There was a statistically significant difference in the mean tumor thickness between the tumors with aggressive growth pattern and non-aggressive growth pattern (p = 0.033). CONCLUSION: Tumor thickness might have positive correlation with aggressive histological pattern. Measuring and reporting tumor thickness may be a more practical way to determine the pathological risk for BCC.

First case report of Pacinian corpuscle hyperplasia following complex regional pain syndrome.

Pacinian disorders are exceedingly rare, and the exact pathogenesis is still unknown. The most common symptoms are pain, sensory changes, and a visible or palpable mass, and diagnosis is usually made by pathological examination after the excision of the painful nodule. In this case report, we present the case of a 49-year-old male with Pacinian corpuscle hyperplasia located on the metacarpophalangeal joint, emerging at the same hand of the patient two years after the treatment due to complex regional pain syndrome (CRPS). To the best of our knowledge, this is the first case report revealing the association of CRPS with hyperplasia of Pacinian corpuscles.