Johnson, Emma F.

ABSTRACT Myhre syndrome is a rare multisystem disorder characterized by distinctive facial features, hearing loss, and progressive fibrosis affecting the skin, joints, lungs, and cardiovascular system. It is caused by heterozygous pathogenic variants in the SMAD4 gene. In this review, we detail the cutaneous manifestations observed in two previously reported patients with genetically confirmed Myhre syndrome. While skin biopsies demonstrated pan‐dermal thickening of collagen bundles, the immunohistochemical staining patterns were distinct from those seen in other inflammatory sclerosing disorders. Additionally, we conducted a comprehensive literature review of the cutaneous features associated with Myhre syndrome, identifying 175 patients with confirmed SMAD4 pathogenic variants. The most reported cutaneous finding was thickened or stiff skin (76%), followed by keratosis pilaris (22%) and impaired wound healing or abnormal scarring (18%). Genotype–phenotype analysis suggested a diagnostic delay in patients with the codon 496 variant, who were more frequently diagnosed in adulthood. This variant may also be associated with a milder cutaneous phenotype, highlighting the clinical heterogeneity of Myhre syndrome. These findings underscore the importance of recognizing cutaneous features as potential early diagnostic clues in patients with suspected Myhre syndrome.

Patzelt et al. previously characterized dermal-binding autoantibodies using an indirect immunofluorescence (IIF) mosaic assay with cells transfected with p200-laminin β4, laminin-332 or collagen VII subunits among specimens showing a dermal pattern on IIF using salt-split skin (IIF-SSS) and IgG. This study expanded testing to include specimens with either a dermal or mixed pattern on IIF-SSS and demonstrated improved test sensitivity with modified testing methods.

Abstract Langerhans cell histiocytosis (LCH) is a rare histiocytic disorder infrequently complicated by delayed-onset pituitary disease. A 41-year-old female presented with papular, acneiform skin lesions. Shave biopsy demonstrated a superficial dermal epithelioid cell proliferation with S100, CD1a, and langerin positivity on immunohistochemistry and a BRAF p.N486_P490del inframe deletion-gain of function pathogenic variant on next-generation sequencing. The skin lesions spontaneously resolved. One year later, she developed progressive fatigue, fevers, anorexia, menstrual irregularities, polyuria, and polydipsia. Laboratory workup was consistent with panhypopituitarism. Pituitary magnetic resonance imaging noted mass-like thickening and enhancement of the infundibulum extending toward the hypothalamus. After treatment with cobimetinib, magnetic resonance imaging findings resolved but endocrinopathies persisted, requiring indefinite hormone therapy. This case demonstrates the full spectrum of endocrinopathies of LCH-induced pituitary disease and is an unusual circumstance of LCH with delayed-onset panhypopituitarism.

ABSTRACTBackgroundDrug‐induced hypersensitivity syndrome (DiHS), or drug reaction with eosinophilia and systemic symptoms (DRESS), is a delayed and severe immune response to certain medications. We investigated vancomycin‐induced DiHS/DRESS, notable for frequent and severe organ involvement, to describe its specific histopathology and the correlations between histopathologic and clinical findings.MethodsA retrospective review was conducted to identify patients between 2006 and 2022 who received vancomycin, had archived skin biopsy specimens, and were scored as having probable or definite DiHS/DRESS. Clinical features were retrospectively collected, and biopsy specimens were reviewed by a board‐certified dermatopathologist. A subset of histopathologic and clinical features was analyzed for statistical correlation.ResultsTwenty‐three patients met the inclusion criteria. Most biopsy specimens (87%) showed an eczematous reaction pattern; 17 (74%) showed a secondary reaction pattern. Spongiosis (87%) and neutrophilic infiltration (91%) were common epidermal characteristics. The dermal inflammatory infiltrate was frequently superficial (87%) and consistently included plasma cells (96%). Eosinophils were present in the dermis in 70% of cases. Parakeratosis negatively correlated with liver involvement and positively correlated with desquamative rash. Epidermal lymphocytes were negatively correlated with the RegiSCAR score.ConclusionsVancomycin‐associated DiHS/DRESS histopathology was characterized by a frequent eczematous reaction pattern, multiple coexisting reaction patterns, and epidermal neutrophilic infiltration.

A healthy 19-year-old man with Fitzpatrick skin type V presented with a 2-year history of smooth, firm, skin-colored papules on the nasal dorsum and bilateral alae. What is your diagnosis?

ABSTRACTBackgroundThere is a known association between common variable immunodeficiency (CVID) and granulomas in multiple organ systems, including the skin, lung, liver, and spleen. Rubella virus has also been detected within cutaneous granulomas in both immunocompetent and immunocompromised hosts. We present a retrospective case series of patients with CVID and granulomatous skin disease and describe the spectrum of clinical and histopathologic features, including the status of rubella virus in the cutaneous granulomas.MethodsWe retrospectively reviewed the clinical and histopathological characteristics of patients diagnosed with CVID at our institution, with cutaneous findings and skin biopsies available for review between 1990 and 2023, demonstrating granulomatous inflammation.ResultsEight patients met the inclusion criteria. The most common histopathologic pattern was palisaded granulomatous inflammation, seen in five of eight cases. Three cases showed strictly sarcoidal granulomas. Background inflammation was peri‐granulomatous (8/8) and the predominant background inflammatory cell type was lymphocytic (6/8). Rubella virus testing was performed for seven of eight cases and found to be positive in one case.ConclusionCutaneous granulomatous disease in CVID can present with a spectrum of clinical morphologies, granulomatous patterns, and variable rubella virus persistence. Dermatopathologists should be aware of the spectrum of findings when considering cutaneous CVID–related granulomatous disease in the differential diagnosis.

Background: Maculopapular cutaneous mastocytosis (MPCM) is a rare disorder characterized by a pathologic accumulation of mast cells in the skin, which may or may not be accompanied by systemic mastocytosis. Diagnosis of MPCM on skin biopsy can be challenging because the findings may be subtle. Although mast cell density in MPCM has been reported, data informing a proposed cutoff for diagnosis and diagnostic criteria are limited. Methods: We identified adult patients diagnosed with MPCM and urticarial tissue reaction/chronic urticaria on skin biopsy and compared the mast cell and eosinophil counts per 1 mm2 in 10 cases each of MPCM, chronic urticaria, and normal skin from routine biopsies. All slides were stained with CD117, and CD117-positive mast cells were counted per 1 mm2 using digital microscopy. Eosinophils were counted on hematoxylin and eosin-stained slides per 1 mm2 using digital microscopy. Results: The median number of mast cells per 1 mm2 was significantly higher in MPCM than in cases of urticaria and normal skin/control tissue (177.3 vs. 26.8 vs. 47.8 mast cell per mm2, respectively; P ≤ 0.001). The calculated “cut point” for mastocytosis versus chronic urticaria and normal skin was 66 mast cells per 1 mm2, whereas the value for controls versus urticaria was 37 mast cells per 1 mm2. Eosinophils had similar density in MPCM and urticaria, and their presence was significant in the differentiation of MPCM and urticaria from normal tissue. Conclusions: This study adds to the literature by providing objective mast cell density data to distinguish challenging cases of cutaneous mastocytosis from urticarial reactions and normal skin. Future studies could explore the development of computer-aided estimations of cellular density with more extensive comparison with other inflammatory conditions to translate our findings more readily into clinical practice.

Abstract: There is a paucity of data regarding porokeratosis confined to the penis and scrotum. We evaluated our single-institutional experience regarding this entity. We interrogated our pathology archive for all specimens from the penis or scrotum, signed out as porokeratosis between 2000 and 2022. Clinical and histopathological features were reviewed, including the number of cornoid lamella(e) per tissue profile and squamous dysplasia. Nine patients were included in the study. The median age at the time of diagnosis was 51 years. Multiple lesions were present in 3 patients. Six patients had exclusively penile involvement, whereas 2 patients had exclusively scrotal involvement. One patient had multiple lesions consistent with porokeratosis ptychotropica, extending from the scrotum to the buttocks and perineum. Clinically, a collarette of scale was noted in 3 patients and diagnosis of porokeratosis was considered in 1 patient before biopsy. Histopathologically, 2 patients exhibited multiple cornoid lamellae in the same profile and 1 patient had follicular cornoid lamellae. Focal squamous dysplasia was only present in 1 patient. Follow-up was available for 5 patients (median duration: 35 months). In 4 patients, the lesions were removed completely during the shave biopsy procedure. At the past follow-up, there were no signs of recurrence or malignant transformation to squamous cell carcinoma in any patient. Porokeratosis involving the penis and/or scrotum may be elusive to diagnosis based on clinical features alone, emphasizing the role of histopathological examination. Increased awareness of this entity may help better delineate its clinicopathological presentation and appropriate classification.