2016 Essentials of Dermatopathology Slide Library Handout Book April 8-10, 2016 JW Marriott Houston Downtown Houston, TX USA CASE #01 -- SLIDE #01 Diagnosis: Nodular fasciitis Case Summary: 12 year old male with a rapidly growing temple mass. Present for 4 weeks. Nodular fasciitis is a self-limited pseudosarcomatous proliferation that may cause clinical alarm due to its rapid growth. It is most common in young adults but occurs across a wide age range. This lesion is typically 3-5 cm and composed of bland fibroblasts and myofibroblasts without significant cytologic atypia arranged in a loose storiform pattern with areas of extravasated red blood cells. Mitoses may be numerous, but atypical mitotic figures are absent. Nodular fasciitis is a benign process, and recurrence is very rare (1%). Recent work has shown that the MYH9-USP6 gene fusion is present in approximately 90% of cases, and molecular techniques to show USP6 gene rearrangement may be a helpful ancillary tool in difficult cases or on small biopsy samples. Weiss SW, Goldblum JR. Enzinger and Weiss’s Soft Tissue Tumors, 5th edition. Mosby Elsevier. 2008. Erickson-Johnson MR, Chou MM, Evers BR, Roth CW, Seys AR, Jin L, Ye Y, Lau AW, Wang X, Oliveira AM. Nodular fasciitis: a novel model of transient neoplasia induced by MYH9-USP6 gene fusion. Lab Invest. 2011 Oct;91(10):1427-33. Amary MF, Ye H, Berisha F, Tirabosco R, Presneau N, Flanagan AM. Detection of USP6 gene rearrangement in nodular fasciitis: an important diagnostic tool. Virchows Arch. 2013 Jul;463(1):97-8. CONTRIBUTED BY KAREN FRITCHIE, MD 1 CASE #02 -- SLIDE #02 Diagnosis: Cellular fibrous histiocytoma Case Summary: 12 year old female with wrist mass. Fibrous histiocytoma is a lesion composed of a polymorphous proliferation of foamy histiocytes, multinucleated giants cells (some of which can be Touton giant cells), bland spindle cells and inflammatory cells. One of the most helpful histologic clues to this diagnosis is the prominent collagen trapping at the edge of the lesion. Clinically, fibrous histiocytoma usually presents as a solitary slow-growing nodule in early or middle-adult life. It is most common on the extremities. Many variants of fibrous histiocytoma exist including cellular fibrous histiocytoma, aneurysmal fibrous histiocytoma, epithelioid fibrous histiocytoma and atypical fibrous histiocytoma. Cellular fibrous histiocytoma differs from the conventional form by its monomorphous appearance (typically only bland spindle cells) and lack of secondary elements (giant cells, foamy histiocytes). The characteristic collagen entrapment is still present. Due to the relatively high rate of local recurrence of cellular fibrous histiocytoma (approximately 20%), complete surgical excision is usually recommended. CONTRIBUTED BY KAREN FRITCHIE, MD 2 CASE #03 -- SLIDE #03 Diagnosis: Dermatofibrosarcoma protuberans Case Summary: 25 year old female with breast mass. Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive tumor that usually presents during early or middle adulthood. Although there appears to be an increasing number of reports in children, this diagnosis remains relatively rare in the pediatric population. Histologically, DFSP is composed of a diffusely infiltrative proliferation of uniform CD34-positive spindle cells arranged in a storiform architecture. Typically the tumor cells can be seen infiltrating subcutaneous adipose tissue in a ‘honeycomb’ pattern. Areas with myxoid morphology may also be present. This tumor has a high recurrence rate if not completely excised, but the rate of metastatic disease is low. Cytogenetically DFSP is characterized by supernumerary ring chromosomes derived from chromosome 22 or by the presence of the reciprocal translocation t(17;22). At the molecular level, both cytogenetic abnormalities result in the fusion of COL1A1 on chromosome 17q to PDGFB on chromosome 22q. The COL1A1/PDGFB fusion activates the PDGFRB tyrosine kinase signaling pathway, which renders DFSP responsive to tyrosine kinase inhibitors, such as imatinib mesylate. Weiss SW, Goldblum JR. Enzinger and Weiss’s Soft Tissue Tumors, 5th edition. Mosby Elsevier. 2008. Simon MP, Pedeutour F, Sirvent N, Grosgeorge J, Minoletti F, Coindre JM, Terrier-Lacombe MJ, Mandahl N, Craver RD, Blin N, Sozzi G, Turc-Carel C, O'Brien KP, Kedra D, Fransson I, Guilbaud C, Dumanski JP.Deregulation of the platelet-derived growth factor B-chain gene via fusion with collagen gene COL1A1 in dermatofibrosarcoma protuberans and giant-cell fibroblastoma. Nat.Genet., 1997. 15(1): p. 95-98. Ugurel S, Mentzel T, Utikal J, Helmbold P, Mohr P, Pfohler C, Schiller M, Hauschild A, Hein R, Kampgen E, Kellner I, Leverkus M, Becker JC, Strobel P, Schadendorf D.Neo-adjuvant imatinib in advanced primary or locally recurrent dermatofibrosarcoma protuberans: a multicenter phase-II DeCOG trial with long-term follow-up. Clin Cancer Res. 2013 Oct 30. CONTRIBUTED BY KAREN FRITCHIE, MD 3 CASE #04 -- SLIDE #04 Diagnosis: Giant cell fibroblastoma Case Summary: 18 year old male with axillary mass. Although Shmookler and Enzinger who first described giant cell fibroblastoma in 1982 suggested that it was related to dermatofibrosarcoma protuberans (DFSP), it was not until 1996 when this theory was proven by cytogentic studies. Both giant cell fibroblastoma and DFSP are linked by supernumerary ring chromosomes derived from chromosomes 17 and 22. Giant cell fibroblastoma develops as a painless nodule in the dermis or subcutaneous tissue most commonly in infants and children. Sites affected include thigh, inguinal region and chest wall. Histologically these tumors are composed of a loose arrangement of spindle cells with an infiltrative growth pattern. The cellularity of this lesion is quite variable, but a common morphologic feature includes pseudovascular spaces lined by giant cells. These tumors are CD34 positive, like DSFP. Treatment of giant cell fibroblastoma should be wide local excision. Jha P, Moosavi C, Fanburg-Smith JC. Giant cell fibroblastoma: an update and addition of 86 new cases from the Armed Forces Institute of Pathology, in honor of Dr. Franz M. Enzinger. Ann Diagn Pathol. 2007 Apr;11(2):81-8. Dal Cin P, Sciot R, de Wever I, Brock P, Casteels-Van Daele M, Van Damme B, Van Den Berghe H. Cytogenetic and immunohistochemical evidence that giant cell fibroblastoma is related to dermatofibrosarcoma protuberans. Genes Chromosomes Cancer. 1996 Jan;15(1):73-5. CONTRIBUTED BY KAREN FRITCHIE, MD 4 CASE #05 -- SLIDE #05 Diagnosis: Hemangioma. Case Summary: 26 year old female with chest wall mass. Hemangioma, a benign vascular tumor, is one of the most common soft tissue tumors and usually presents in infancy and childhood. Any site can be affected. There are several morphologic variants including capillary (lobular), cavernous and intramuscular. Most have overlapping histiologies, and it is not uncommon to see both capillary and cavernous features in the same lesion. A helpful histologic clue to the benign nature of hemangioma is its low power architecture: circumscribed and often lobular. This contrasts with angiosarcoma which is typically infiltrative. Additionally, the vascular spaces of hemangioma are lined by bland endothelial cells. The vascular spaces of angiosarcoma are poorly formed, while the endothelial population exhibits hyperchromasia and atypia. By immunohistochemistry, the endothelial cells of hemangioma will be positive for markers such as CD31, CD34, FLI-1 and ERG. CONTRIBUTED BY KAREN FRITCHIE, MD 5 CASE #06 -- SLIDE #06 Diagnosis: Angiosarcoma Case Summary: 57 year old male with supraclavicular mass. Angiosarcomas are malignant vascular tumors. While angiosarcomas can be broken down into several clinical subgroups (cutaneous angiosarcoma, angiosarcoma associated with lymphedema, radiation-associated angiosarcoma, angiosarcoma of the breast, angiosarcoma of deep soft tissue), all forms are highly aggressive tumors characterized by an infiltrative proliferation of vascular structures lined by atypical endothelial cells. In poorly differentiated angiosarcoma, the endothelial nature may be difficult to recognize. In those cases, immunohistochemistry for CD31, CD34, FLI-1 and ERG may be helpful. It is not uncommon for angiosarcoma to lose reactivity for one or more endothelial markers, so sometimes a panel of immunostains may be necessary. The prognosis for patients with angiosarcoma is poor. Recent work has revealed that post-radiation angiosarcomas are characterized by MYC amplification. Additional studies have shown the either immunohistochemistry for MYC overexpression or FISH for MYC overamplification is a helpful diagnostic tool for differentiating post-radiation angiosarcoma from atypical vascular lesions (AVLs). Mentzel T, Schildhaus HU, Palmedo G, Büttner R, Kutzner H. Postradiation cutaneous angiosarcoma after treatment of breast carcinoma is characterized by MYC amplification in contrast to atypical vascular lesions after radiotherapy and control cases: clinicopathological, immunohistochemical and molecular analysis of 66 cases. Mod Pathol. 2012 Jan;25(1):75-85. CONTRIBUTED BY KAREN FRITCHIE, MD 6 CASE #07 -- SLIDE #07 Diagnosis: Epithelioid hemangioma Case Summary: 11 year old female with postauricular mass. Epithelioid hemangioma (angiolymphoid hyperplasia with eosinophilia) is a distinct vascular tumor that usually presents in young or middle-aged adults. The most common site of involvement is the dermis/subcutateous tissue around the ear. About 50% of patients will describe multiple lesions. Histiologically,