Oral Lymphomatoid papulosis type C: A diagnostic pitfall, often confused with T-cell lymphoma.

Eosinophilic ulcer of the oral mucosa (EUOM) is a rare, benign, self-resolving lymphoproliferative disorder, which typically presents with asymptomatic to mildly tender ulcers. Histological findings of EUOM are characterized by a polymorphic infiltrate with many eosinophils often extending into the underlying muscle. Although this entity is well documented within the dental literature, it is not well known to physicians. The pathogenesis of the condition is unclear, although reports dating back to 1997 suggest that at least a subset of EUOM represents CD30 positive lymphoproliferative disorder (CD30+ LPD). More specifically the original report and subsequent authors suggest that the patients fall on the spectrum of CD30+ LPD most reminiscent of Lymphomatoid papulosis (LyP) seen in the skin. This oral variant of LyP would be expected to have the same diverse morphologic spectrum as that seen in cutaneous LyP. We present five EUOM patients whose biopsies showed an atypical lymphocytic infiltrate most compatible with Type C LyP, a histologically unique subset of LyP, reminiscent of the biopsy findings encountered in the reported case by Ficarra and co-workers. (Ficarra, et al., 1997) In four of the five cases, the biopsies were interpreted by expert hematopathologists as an aggressive form of peripheral T cell lymphoma resulting in recommendations to administer systemic chemotherapy to four of the patients, the scheduling of one patient for induction therapy and transplantation before revision of the diagnosis, and administration of chemotherapy to one of the patients. The natural clinical course of spontaneous regression refuted the original diagnoses as a form of aggressive peripheral T cell lymphoma. Recognition of oral LyP is critical to avoid inadvertent exposure to potentially toxic chemotherapeutic regimens intended for the treatment of high grade lymphoma.

Hypertrophic Lichenoid Eruption in a Child Successfully Treated Using Acitretin and Surgery: A Case Report and Literature Review.

A 9-year-old boy presented with a history of keratotic violaceous plaques on the limbs and face for 8 years that had gradually progressed to erosive nodules on the extremities for 2 years. Several biopsies revealed hyperkeratosis, liquefactive degeneration of the basal layer, and a bandlike predominantly lymphocytic infiltrate. Based on the clinical and histologic findings, the patient was diagnosed with keratosis lichenoides chronica, a rare chronic dermatosis that is particularly uncommon in childhood. There are fewer than 20 reported cases of pediatric-onset keratosis lichenoides chronica in the current literature, with occurrence of pseudoepitheliomatous hyperplasia of primary keratosis lichenoides chronica lesions being even rarer. Here we present a unique pediatric-onset case accompanied by pseudoepitheliomatous hyperplasia that posed a significant treatment challenge to dermatologists. Significant improvement in the pseudoepitheliomatous skin lesions was achieved after treatment with oral acitretin capsules and surgical excision with skin grafting.

Combined melanocytic and sweat gland neoplasm: cell subsets harbor an identical HRAS mutation in phacomatosis pigmentokeratotica.

Phacomatosis pigmentokeratotica (PPK) is characterized by the co-existence of epidermal nevi and large segmental speckled lentiginous nevi of the papulosa type. PPK, previously explained as 'twin spot' mosaicism due to the postzygotic crossing-over of two homozygous recessive mutations, has recently been shown to derive from one postzygotic activating RAS mutation. Epidermal nevi, including those in PPK, are known to give rise to neoplasms such as trichoblastoma and basal cell carcinoma. Within speckled lentiginous nevi, Spitz nevi and melanoma have been well documented. We report a case of PPK with a combined melanocytic and adnexal neoplasm presenting where the nevi conjoined. Using next-generation sequencing techniques, we were able to identify the same HRAS G13R mutation within both components of the tumor, and to show the absence of additional mutated modifier genes in a panel of 300 cancer-related genes. Given the genetic findings in this rare tumor-type, we suggest that this case may be used as a model for understanding the development of biphenotypic neoplasia or intratumoral heterogeneity in some cases.

Necrotizing sarcoid granulomatosis with skin and pulmonary involvement.

We present a rare case of necrotizing sarcoid granulomatosis (NSG) with skin and pulmonary involvement. NSG with extrapulmonary involvement occurs infrequently, and reports involving skin manifestations in NSG are even more rare.