S98 © American Society for Clinical Pathology AJCP / Meeting AbstrActs Am J Clin Pathol 2020;154:S21-S168 DOI: 10.1093/ajcp/aqaa161 Case Series: Seventeen Year Institutional Review of Placental Chorangiomas A. Kousar 1 , K. Takeda 1 , A. Rizvi 1 , A. Sutton 1 , K. Geisinger 1 ; 1 Pathology, Vidant Medical Center/East Carolina University, Greenville, North Carolina, UNITED STATES| Introduction/Objective: Chorangioma is a rare tumor occurring in less than 0.5 - 1% of all pregnancies. Small chorangiomas (< 4cm) are mostly asymptomatic and in- cidental. Large chorangiomas (> 4 cm) may be associated with various fetal complications and complicated preg- nancies. The aim of our study is to assess the ultrasound detection rate of these lesions. Methods: A retrospective study of chorangioma cases seen at Vidant Medical Center between 2003 to 2019 was conducted. Size of the lesion, detection on prenatal imaging, gestational weeks at delivery, maternal age and pregnancy related fetal and maternal complications were analyzed. Results: A total of 25761 placentas were examined from 2003 to 2019 in Vidant Medical Center. Out of these only thirty-nine cases (0.15%) of chorangioma were found. 41% of these women were above 30 years of age. 36 patients were non-Hispanic. 92.3 % (36 cases) of these lesions were less than 4cm and 7.6 %(3 cases) were above 4 cm, with only one recent case of 7.0 cm in greatest dimension. 92% of the total patients presented with complicated pregnan- cies. Preeclampsia, preterm delivery, gestational hyper- tension and intrauterine growth retardation were among the most common complications observed. 3 patients pre- sented with oligohydramnios. Interestingly, none of the lesions were detected on prenatal ultrasound. Conclusion: Large chorangiomas(>4 cm) are rare but are known to be associated with adverse fetal outcomes. Our seventeen year institutional review shows the largest chorangioma to be 7 cm in greatest dimension. Regular ultrasound monitoring is required to pick up these benign lesions early and prevent adverse outcomes. A retrospec- tive review is needed to determine why the lesions in our study were not detected radiographically. Cutaneous Plasmacytosis: A Pitfall For B and Plasma Cell Neoplasms C.N. Giraldo 1 , D. Myers 1 , A. Holmes 1 , J. Dodd 2 , W. Wendi 2 ; 1 Pathology, Brooke Army Medical Center, San Antonio, Texas, UNITED STATES|, 2 Dermatology, Brooke Army Medical Center, San Antonio, Texas, UNITED STATES| Introduction/Objective: Cutaneous plasmacytosis (CP) is an uncommon condition typically affecting Asian males in the 3rd to 5th decades. It is thought to be a reactive process that classically presents with asymptomatic, red-brown, plaques and nodules on the face and neck. It has been associated with polyclonal hypergammaglobulinemia and systemic involvement. Histologically it is characterized by dense superfcial and deep dermal infltrates of mature plasma cells with polyclonal differentiation on in-situ hybridization (ISH). The differential diagnosis includes neoplastic plasma cell processes, characteristically with monoclonal plasma cell infltrate, and mature B cell neo- plasms with polyclonal plasma cell differentiation. Methods: We report a case of a 69 year old Caucasian male who presented with asymptomatic, enlarging red-brown nodules on bilateral nasal ala. Histologic examination re- vealed dense, superfcial plasma cell infltrate, concerning for a plasma cell neoplasm. CD138 and Kappa/Lambda ISH demonstrated plasma cell polyclonality. Further workup ruled out infectious or systemic involvement and a plasma cell dyscrasia was ruled out by Hematology/ Oncology. Results: These fndings supported the diagnosis of CP. Treatment with intralesional steroids showed initial im- provement with regrowth of the nodules. To date, treat- ment with topical steroids and CO2 laser ablation are being considered. Conclusion: CP is reported as type of pseudolymphoma, which is described as a reactive lymphoproliferation that histopathologically and/or clinically imitates cutaneous lymphoma. The pathogenesis is unknown, however, there are studies suggesting an association with increased inter- leukin-6, which is involved in the differentiation of B cells to mature plasma cells. The majority of patients with CP have a favorable prognosis. There has been variable suc- cess with both topical and intralesional treatment to in- clude, cyclophosphamide, topical tacrolimus, prednisone, intralesional steroid therapy, topical psoralens combined with ultraviolet A exposure, and other chemotherapies. Familiarity with this rare entity is imperative to prevent misdiagnosis and overtreatment. An Unusual Case of Basal Cell Carcinoma with Myoepithelial Differentiation D. Myers 1 , N. Smith 1 ; 1 Pathology, SAUSHEC, Fort Sam Houston, Texas, UNITED STATES| Introduction/Objective: Basal cell carcinoma (BCC) is a commonly encountered dermatologic entity by general surgical pathologists and dermatopatholgists alike and usually does not pose a diagnostic dilemma. However, BCC can take on a variety of histopathologic morpholo- gies, sometimes mimicking more malignant entities. We present an unusual case of BCC with a rare morphology. Methods: A 56-year-old male with history of non- melanoma skin cancer presented to his dermatologist with Downloaded from https://academic.oup.com/ajcp/article/154/Supplement_1/S98/5942164 by guest on 04 August 2022