Johnson, Emma F.

AbstractIgA vasculitis is a small‐vessel vasculitis subtype with increased risk of systemic involvement. We aimed to investigate if any light‐microscopic features can predict the presence of perivascular granular IgA deposits on direct immunofluorescence (DIF) microscopy. We performed a retrospective search of cutaneous pathology reports from our internal and consultation practice (January 1, 2010–October 5, 2021) with a diagnosis of leukocytoclastic vasculitis and accompanying DIF. A blinded dermatopathologist reviewed standard microscopy slides for predetermined histopathological features. Fifty‐six biopsies (48 patients) and 56 biopsies (42 patients) met inclusion criteria for IgA+ and IgA−, respectively. The presence of eosinophils and mid and deep dermal inflammation were statistically more associated with IgA− (41/56 [73.2%] and 31/56 [55.4%], respectively) than IgA+ cases (28/56 [50.0%] and 14/56 [25.0%]; p = 0.049 and 0.006, respectively, chi‐squared test). Other microscopic criteria recorded were not significantly different between the two groups (p > 0.05, chi‐squared and Fisher's exact tests). In this retrospective study of 112 cases, we found that while the absence of eosinophils and absence of mid‐ and deep inflammation were correlated with increased likelihood of IgA perivascular deposition on DIF, no other histopathological features on light microscopy tested could reliably predict the presence of IgA perivascular deposition on DIF. Therefore, DIF remains a necessary component for the accurate diagnosis of cutaneous IgA vasculitis.

AbstractBackgroundFollicular mucinosis (FM) is a rare disease characterized by mucin accumulation in the follicular unit. FM's etiology is still widely debated since its first description in 1957. Follicular mucinosis is usually reported to be benign in children, although reports of malignant transformation, most commonly mycosis fungoides, exist. The present project aims to demonstrate that children with a diagnosis of follicular mucinosis have positive long‐term outcomes and do not develop mycosis fungoides.Materials and methodsThis is a retrospective cohort study where patients with a diagnosis of follicular mucinosis ages 22 years and below were identified. Data surrounding the patient's diagnosis of FM, differential diagnosis, treatments, and long‐term outcomes were collected. Patients who were lost to follow‐up were contacted by phone for an update on the status of their skin and overall health.ResultsOut of 14 patients with follow‐up information, none developed subsequent mycosis fungoides or other hematologic malignancies.ConclusionPediatric patients with follicular mucinosis will likely present with limited disease and not experience malignant transformation.

Abstract Background Pemphigoid gestationis (PG) and polymorphic eruption of pregnancy (PEP) are pregnancy‐related dermatoses. Definitive diagnosis often relies upon histopathology and direct immunofluorescence (DIF). PG is associated with fetal and neonatal risks, while PEP confers minimal risk. Objective We aimed to compare histopathologic features to determine key differentiators. Methods A retrospective cohort study of PG and PEP cases, with accompanying DIF, conducted from 1995 to 2020. Skin biopsies were examined independently in a blinded fashion by two dermatopathologists for a list of histopathological features. Results Twenty‐one cases of PG and 10 cases of PEP were identified. PG had significantly denser eosinophils than PEP (mean 155 vs. 48 cells/5 hpf; p < 0.018). PG was also noted to have eosinophilic spongiosis and eosinophils at the dermal–epidermal junction more frequently compared to PEP (80% PG vs. 10% PEP; p < 0.001). A mean cutoff value of 86 eosinophils and a mean optimal sensitivity and specificity of 81% and 83%, respectively, for eosinophils density's diagnostic power of PEP versus PG were achieved. Subepithelial separation was exclusively seen in PG (40% vs. 0%; p < 0.007). Conclusion Eosinophilic spongiosis, eosinophilic epitheliotropism, and dense superficial dermal eosinophils were diagnostic of PG. Given overlapping clinicopathologic features, however, DIF results with clinicopathologic correlation, remain the gold standard.

Abstract Background Reactive granulomatous dermatitis (RGD) is an umbrella term used to describe interstitial granulomatous dermatitis (IGD), palisaded neutrophilic and granulomatous dermatitis (PNGD), and interstitial granulomatous drug eruption (IGDR). Objective The aim of this study was to describe systemic associations of RGD, explore possible associations between histopathologic findings and systemic RGD associations and determine clinical relevance of RGD subtypes. Methods We retrospectively studied clinical and histopathologic characteristics of patients with RGD from 1990 through 2020. Results Of 65 patients with RGD (41 women, 24 men; median age at diagnosis, 62 years), 37 had IGD, 26 had PNGD, and 2 had IGDR. Fifty patients (76.9%) had an associated systemic condition; rheumatologic conditions were identified for 34 (52.3%) patients. The associated systemic condition occurred before RGD in approximately 75% of patients. Statistical analyses did not show significant associations between specific subtypes of RGD and systemic diseases or treatment response, and specific histopathologic findings were not predictive of an associated systemic disease. Conclusions Although most patients with RGD had an associated systemic condition, subtypes of RGD did not correlate with systemic associations, lending support to the use of the umbrella term RGD .

AbstractBackgroundNecrobiosis lipoidica (NL) is an uncommon granulomatous dermatosis that can occur in patients with or without associated diabetes mellitus (DM). Prior studies have attempted to determine distinctive histopathologic features of NL in patients with and without DM.MethodsA retrospective review of 97 patients with NL was performed to determine the similar and distinctive histopathologic features in patients with DM and without DM.ResultsOf the 97 patients, 32% (n = 31) had DM. Epidermal acanthosis was seen more commonly in diabetics than nondiabetics (32.3% vs. 12.1%; p = 0.017). Naked (sarcoidal/tuberculoid) granulomas were more frequently observed in nondiabetics than diabetics (22.7% vs. 3.2%; p = 0.016). Eosinophils were more common in nondiabetics than diabetics (38.5% vs. 9.7%; p = 0.004), while neutrophilic infiltration was more common in diabetics than nondiabetics (45.2% vs. 17.5%; p = 0.004).ConclusionsThis study corroborates well‐documented histopathologic features of NL and shows distinctive histopathologic features of NL among patients with DM‐I, DM‐II, and without DM. These results support the hypothesis that there are different underlying drivers of NL between diabetics and nondiabetics.

AbstractBackgroundCertain autoimmune bullous dermatoses are mediated by autoantibodies of the IgG4 subclass. We determined the diagnostic impact of adding IgG4 to our conventional direct immunofluorescence (DIF) panel.MethodsFor all cases submitted to our referral laboratory for DIF over 1 month (n = 630), we performed IgG4 testing and collected consecutive biopsy specimens showing definite or indeterminate linear or cell‐surface deposition of IgG, IgG4, and/or C3. On retrospective blinded review, we classified the pattern and whether the findings were definite, indeterminate, or negative. When present, substantial background staining was recorded.ResultsSeventy DIF specimens met the inclusion criteria. Of 22 (31.4%) specimens equivocal for linear or cell‐surface deposition, 9 (40.9%) had definitive IgG4 findings, either linear (3 of 14 equivocal linear cases; 21.4%) or cell‐surface (6 of 8 equivocal cell‐surface cases; 75.0%). Background deposition was substantial in 14 cases (20.0%) for IgG but in none for C3 or IgG4.ConclusionIgG4 allowed the classification of over 40% of DIF cases that were otherwise equivocal by IgG and C3. IgG4 staining showed lower levels of non‐specific background staining than IgG or C3. IgG4 appears to contribute most value in cases with cell‐surface deposition or with equivocal linear IgG deposition and negative C3 results.

AbstractOral cavity lymphomas constitute only 3% of all lymphomas in the general population but are the third most common oral malignancy. A 67‐year‐old female with a history of osteoporosis, Graves’ disease and non‐Hodgkin's lymphoma was referred to the Department of Dental Specialties with a chief complaint of persistent soft tissue swelling facial to the maxillary incisors of possible non‐odontogenic origin. To expedite care, the patient was first seen via teledentistry and subsequently appointed for an in‐person evaluation and treatment. Examination revealed 1–3 mm probing depths and a firm, non‐tender, non‐fluctuant mass in the facial soft tissues approximating teeth nos. 7–10. Biopsy of the affected area was performed. A diagnosis of recurrent follicle center cell lymphoma, a form of non‐Hodgkin's lymphoma, was rendered. The patient was subsequently referred to the Oncology and Hematology team, followed for 6 weeks and remained symptom‐free. This case underlies the importance of teledentistry to expedite care and manage patient expectations. Additionally, it also underscores the importance of microscopic examination of tissue samples from oral lesions that appear non‐odontogenic in nature and reinforces the role of dentistry in uncovering the oral‐systemic link.