Desmoplastic trichilemmoma (DTM) is a rare and benign variant of conventional trichilemmoma which presents a diagnostic challenge. It closely mimics malignant neoplasms, particularly basal cell carcinoma (BCC), because of overlapping clinical and histopathological features. Accurate differentiation is crucial to prevent misdiagnosis and management. The aim of this study was to synthesize the available clinical and histopathological data on DTM by presenting 2 new cases and conducting a systematic review of the literature. A retrospective query was conducted of database from 2012 to 2026 identifying 2 DTM cases. In addition, a systematic review of the PubMed database was performed for English language publications from 1990 to present day, yielding 29 publications for inclusion. The addition of 2 new cases brings the total number of DTMs in the compiled dataset to 94 cases. DTM typically presents as a solitary lesion on the head and neck of older adults, ranging in size from 0.3 to 7 cm, with rare cases reported on the chest, vulva, and lower extremities. Histopathologically, its lobular and cord-like growth pattern, peripheral palisading, and desmoplastic stroma closely mimic BCC. Immunohistochemically, the current cases showed immunoreactivity for CD34 and a concurrent negativity for BerEP4. Based on the current findings and review data, 8 CD34-positive/BerEP4-negative and 10 CD34-positive DTMs were identified. Accurate distinction between DTM and BCC requires careful histological examination, which is enhanced by the application of the proposed CD34-BerEP4 dual-marker approach. This diagnostic utility guides appropriate clinical management and prevents unnecessary or inadequate treatment.

We present the case of a 75-year-old woman with a vulvar collision tumor consisting of basal cell carcinoma (BCC) and primary extramammary Paget disease (EMPD). The patient presented for evaluation of a pigmented nodule on the right labium majus identified 1 year ago. The nodule was excised, and histopathology revealed nests of basaloid cells with nuclear palisading surrounded by myxoid stroma, consistent with nodular BCC. In addition, scattered intraepidermal cells with clear amphophilic cytoplasm at the periphery of the specimen raised suspicion for EMPD coexistence. Further visual inspection revealed bilateral hypopigmented patches on the labia majora. Gynecological and urological examination showed no abnormal findings. The hypopigmented lesion was excised with a 1-cm margin. Histopathology showed an intraepidermal pagetoid spread of tumor cells with atypical nuclei and abundant amphophilic cytoplasm. A diagnosis of a collision tumor comprising BCC and primary EMPD was made. A BCC-EMPD collision is rarely reported. This case highlights that coexisting EMPD can be overlooked, particularly when evaluating vulvar BCC, underscoring the diagnostic challenge posed by basaloid proliferation and pagetoid spread. Furthermore, our review of the literature elucidated the unique clinicopathological features of BCC-EMPD collision and discussed its differentiation from secondary EMPD with Pinkus-like changes and BCC with pagetoid spread.

Lipschütz ulcers, also known as non-sexually acquired acute genital ulcers, are rare lesions that primarily affect adolescent and prepubertal females. Their sudden onset, severe pain, and dramatic appearance can be alarming, often mimicking infectious or autoimmune diseases. A 10-year-old girl presented with severe perineal pain, dysuria, and fever following an episode of pharyngotonsillitis. Examination revealed vulvar ulcers. A diagnosis of Lipschütz ulcers associated with pharyngotonsillitis was established. Supportive therapy led to gradual improvement. This case illustrates the diagnostic challenges of acute vulvar ulcers in pediatric patients and highlights the importance of recognizing Lipschütz ulcers to avoid unnecessary treatments. Although rare, Lipschütz ulcers should be considered in the differential diagnosis of acute genital ulcers in children, especially following systemic illness.

Plasma cell vulvitis (PCV), also referred to as Zoon's vulvitis, is a rare and chronic inflammatory condition of the vulva characterized by distinctive red, glistening patches with a subtle red-orange hue. The condition can be asymptomatic or present with symptoms such as discomfort, dyspareunia, and pruritus, often mimicking other vulvar mucosal disorders like lichen planus. Due to its rarity and the overlap of symptoms with more common vulvovaginal conditions, PCV is frequently underreported and misdiagnosed. The exact etiology of PCV remains unclear, with possible associations to herpes simplex virus (HSV) and abnormal immune responses being hypothesized. This manuscript presents a case of PCV in a 46-year-old female who presented with a red, glistening, focally ulcerated patch on the vulva.

Vulvovaginal squamous cell carcinoma (SCC) is an uncommon neoplasm in dogs. An 11-year-old female spayed German Shepherd dog presented with a history of excessive peri-vulvar grooming and a 3 cm × 3 cm irregular mass involving the vagina and vulva. Incisional biopsy confirmed a diagnosis of primary vulvovaginal SCC. Abdominal ultrasonography and thoracic radiographs indicated no evidence of systemic or regional metastasis. Surgical excision and adjuvant radiation therapy were declined, and the patient was treated with lapatinib, an orally administered dual tyrosine kinase inhibitor. Treatment resulted in a partial response within 1 month and complete resolution of the primary lesion within 3 months. No recurrence of the initial lesion was observed after 1 year of treatment despite development of perivulvar cutaneous lesions that were not associated with clinical signs. Lapatinib was well tolerated but did result in acute hepatic injury that was resolved using hepatoprotective antioxidant medication and intermittent treatment cessation.

Nodular fasciitis (NF) is a benign, self-limited myofibroblastic proliferation that typically arises in the subcutaneous tissues of the extremities and trunk, while vulvar involvement is distinctly rare. Owing to its rapid growth and histologic features, NF may mimic both benign and malignant lesions, creating significant diagnostic challenges. We report a case of a 34-yr-old woman presenting with a rapidly enlarging, painless vulvar mass initially suspected to represent a Bartholin gland cyst. Gross examination revealed a 2.5 cm, well-defined lesion with a tan, glistening cut surface. Microscopically, the lesion was unencapsulated and composed of spindle cells arranged in a storiform pattern with alternating cellularity, set within a myxoid and collagenous stroma. Extravasated erythrocytes and occasional osteoclast-like giant cells were present, while cytologic atypia and necrosis were absent. Mitotic activity was low. Immunohistochemically, the lesion showed diffuse smooth muscle actin expression and was negative for CD34, desmin, ALK, cytokeratin, estrogen receptor, progesterone receptor, and STAT6 with retained RB1 expression and membranous β-catenin staining. Next-generation sequencing identified a MYH9:::USP6 fusion, confirming the diagnosis. This case highlights the importance of recognizing nodular fasciitis in the vulva as a potential diagnostic pitfall, particularly in lesions clinically interpreted as Bartholin gland cysts. Integration of morphologic, immunohistochemical, and molecular findings is essential to avoid misdiagnosis and overtreatment.

Vulvar glomus tumors are rare and typically benign, slow-growing tumors. Rapid enlargement is uncommon and may suggest malignancy or other atypical conditions. A 58-year-old postmenopausal woman noticed a small vulvar nodule. After needle aspiration at another hospital, significant bleeding occurred, requiring tumor base ligation. Although hemostasis was achieved, the mass subsequently continued to enlarge rapidly, prompting referral to our hospital. The lesion continued to enlarge gradually, so surgical excision was therefore performed. Histopathological findings confirmed a glomus tumor with atypical features, including a marked edematous stroma. The rapid enlargement was not attributed to malignancy, a hematoma, or an infection, but was considered to represent apparent growth associated with increased edema secondary to vascular congestion within the tumor. The present case highlights that the rapid enlargement of glomus tumor-related lesions does not necessarily indicate malignancy.