Atypical plaque psoriasis: a clinicopathological study of 20 cases.

BACKGROUND: Plaque psoriasis is relatively straightforward to identify. When diagnostic concerns arise in atypical cases, a biopsy is needed. It is widely accepted that the Munro microabscess and the spongiform pustule of Kogoj are diagnostic pathological features. However, the diagnostic dilemma is likely to arise in cases without these specific pathological changes and typical clinical features. This study aimed to investigate clinical and pathological clues in distinguishing atypical plaque psoriasis from its mimics. METHODS: We evaluated the clinicopathological features of 20 cases of atypical plaque psoriasis and 40 cases of psoriasis mimics as controls including pityriasis rosea (n = 10), pityriasis lichenoides chronica (n = 8), and subacute dermatitis (n = 22). RESULTS: A retrospective analysis of the clinicopathological characteristics of patients with atypical plaque psoriasis and controls was performed. Pathologically, there were significant differences between the two groups in the types of parakeratosis (P = 0.046), epidermal capture of extravasated erythrocytes (P = 0.011), focal basal liquefied degeneration (P = 0.017), types of inflammatory cells (P = 0.000), and depth of inflammation (P = 0.000). Clinically, we found the presence of scales and crusts was significantly different between the two groups. CONCLUSION: This study offers insight into the clinicopathological features of atypical plaque psoriasis. These differential diagnostic features, compared with its mimics, are proposed to assist the clinician in the diagnosis and treatment of atypical plaque psoriasis.

Scaly erythematous eruptions of intertriginous locations.

Intertriginous or flexural eruptions are common presenting problems in clinical practice, raising several differential diagnoses. A clinico-histopathological correlation is important to establish a correct diagnosis when a clinical diagnosis cannot be ascertained. We here present a case of flaky erythematous eruptions in a female adult, with a final diagnosis of granular parakeratosis, involving nonflexural area mid-back (under bra cover) in addition to flexural zones of the groin, gluteal fold, inframammary fold and axilla. It seems that mechanism of pressure and friction as well as occlusion all play a part. Management with potent topical steroid and avoidance of inciting triggers offered resolution in 4 weeks in this case.

Granular parakeratosis secondary to benzalkonium chloride exposure from common household laundry rinse aids.

AIM: Granular parakeratosis (GP) is a benign dermatosis characterised by a rash at intertriginous sites. The pathogenesis is uncertain although it is proposed to be an irritant contact reaction with cases related to benzalkonium chloride (BAC) reported. Our experience is that patients often have delayed diagnosis. This study aims to review the clinical presentation and histopathological features of GP. METHODS: This study is a retrospective case series of adult and paediatric patients seen at dermatology clinics in Auckland, New Zealand. Information was collected on patient demographics, presentation, investigations and management. RESULTS: Thirteen cases (seven adults; six children) are included. The typical presentation of GP was erythematous or brown, scaly papules and plaques with desquamation in a predominantly flexural distribution. All patients reported recent exposure to BAC in laundry rinse solution. Nine biopsies were taken from four patients. Psoriasiform and eczematous findings were common on histopathology. The mainstay of treatment was cessation of BAC exposure. CONCLUSION: GP has a distinct clinical pattern although histopathological findings are varied. Clinicians should have a high index of suspicion for GP in patients presenting with erythematous flexural eruptions and seek a history of BAC exposure, especially in the context of the COVID-19 pandemic and increased antiseptic use.

Axillary Granular Parakeratosis.

We describe a case of an 85-year-old Caucasian female who presented to the dermatology clinic with pruritic, scaly hyperpigmented papules and plaques with surrounding erythema in the left axilla. Based on the history and physical examination, there was concern for possible varicella zoster infection, and the patient was started on valacyclovir 1000 mg three times daily for seven days. A shave biopsy was taken from the left axilla to confirm a diagnosis. Microscopic examination revealed compact hyperparakeratosis with keratohyalin granules throughout the parakeratotic stratum corneum as well as admixed eosinophils within the stratum corneum. The epidermis was acanthotic with irregular hyperplasia of the rete ridges. These microscopic findings supported a diagnosis of axillary granular parakeratosis, a benign skin condition caused by a defect in epidermal differentiation. Granular parakeratosis is seemingly rare but is felt to be an underreported condition. It is important for clinicians to be aware of the disease in order to correctly identify the lesions and reassure patients of its benign nature and provide appropriate treatment recommendations.

Caso de paraqueratosis pustulosa: entidad poco frecuente y síntoma de enfermedad inflamatoria del aparato ungueal en pacientes pediátricos / Case of pustular parakeratosis: a rare entity common and symptom of inflammatory disease of the nail apparatus in pediatric patients

La paraqueratosis pustulosa es una entidad poco descrita en la literatura y se define como un proceso inflamatorio cutáneo, ungueal y periungueal en el área distal de un dedo habitualmente pulgar o índice, frecuentemente en la infancia. Su evolución suele ser benigna y la respuesta a emolientes tópicos es favorable. A continuación, se presenta un caso de esta enfermedad con el objetivo de resaltar su consideración en patologías ungueales pediátricas.

Pustular parakeratosis is an entity scantly described in literature. It has been described as a skin, nail, and periungual inflammatory process in the distal area of a finger, usually the thumb or index finger, frequently in childhood. Its evolution is usually benign and management is favorable with topical emollients. A clinical case is presented, to raise awareness of this entity in pediatric nail pathologies.

Lichen planus-like keratosis: clinicopathological evaluation of 1366 cases.

BACKGROUND: Lichen planus-like keratosis (LPLK) is a frequent skin lesion usually biopsied to rule out basal cell carcinoma (BCC). Because of overlapping histopathological characteristics, LPLK is frequently muddled with lichen planus (LP), lichenoid actinic keratosis (LAK), and lupus erythematosus (LE). OBJECTIVE: To investigate the clinical and histopathological characteristics of LPLK. METHODS: A clinicopathologic review was performed of all LPLK cases (1366) signed in one calendar year in a busy academic practice. RESULTS: LPLK occurs mostly as a single lesion (97%) with the chest (41.4%) being the most common site. It is almost equally present in women and men (51.5%-48.5%). The most common clinical concern (65%) is basal cell carcinoma. Parakeratosis, red blood extravasation, and presence of dermal eosinophils and plasma cells, usually not seen in lichen planus, are helpful signs to suggest LPLK but are seen only in a minority of cases. CONCLUSION: Clinicopathologic correlation is necessary to diagnose lichen planus-like keratosis, as the most consistent feature is a clinical history of a lesion/neoplastic process rather than an inflammatory process. There are histopathologic features that can help distinguish lichen planus-like keratosis from lichen planus; however, these features are nonspecific and lacking in almost half of the cases.

Submammary Granular Parakeratosis Treated With Mastopexy.

Granular parakeratosis, originally named axillary granular parakeratosis, is an uncommon disease with an unclear etiology. It is thought to result from defective processing of profillagrin to fillagrin, causing retention of keratohyaline granules in the epidermis. A myriad of causative factors has been proposed, including friction, moisture, heat, and contact irritants such as deodorants. We present a case in the inframammary area that resolved with mastopexy, further supporting the role of friction, moisture, and heat. Furthermore, we present electron microscopic evidence demonstrating non-degraded keratohyaline granules upon epidermal maturation. This entity, we believe, is reactive and represents a protective response of the body to moisture and heat.

J Drugs Dermatol. 2017;16(8):810-812.

The significance of parakeratosis alone in cervicovaginal cytology of turkish women.

BACKGROUND: We aimed to analyze the significance of parakeratosis on an otherwise negative Papanicalaou (Pap) smear, in the absence of any characteristic human papilloma virus (HPV) findings. METHODS: A total of 22,076 Papanicalaou smears that were diagnosed as negative for intraepithelial lesions or malignancy between 2013 and 2015 were included in this study. Samples were separated into two groups, according to the presence of parakeratosis. We investigated the association between parakeratosis in the cytology results and a high-risk HPV status and high-grade squamous intraepithelial lesion (HSIL) in the colposcopic biopsy specimens. RESULTS: A positive HPV result was more frequently identified in cases with parakeratosis than in cases without parakeratosis (P < 0.001). A histological diagnosis of HSIL was more frequently observed in HPV-positive cases with a diagnosis of parakeratosis on cytology than in cases without parakeratosis (P = 0.8). CONCLUSION: Our results demonstrate that a finding of parakeratosis on an otherwise negative Pap smear supports a follow-up HPV DNA test. Also we should consider whether the presence of parakeratosis should be included in standard cytology reports. Additionally parakeratosis trended toward increased frequency of HSIL in follow-up biopsy specimens. But it did not reach statistical significance. That is why larger studies are necessary to evaluate the association of parakeratosis and HSIL in colposcopic biopsy specimens. Diagn. Cytopathol. 2017;45:297-302. © 2016 Wiley Periodicals, Inc.