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47. Primary cutaneous Ewing's sarcoma
S114
PATHOLOGY 2015 ABSTRACT SUPPLEMENT
Conclusion: 1. Mycobacterium avium-intracellulare infection presenting as bowel perforation is uncommon. 2. The two main histological differentials to consider in the small bowel are Whipple’s disease and signet ring cell carcinoma. 3. The Tropheryma whippleii organisms are non acid-fast and gram positive on histochemical staining. PCR is also useful to confirm the diagnosis. 4. The distinction from a carcinoma can be based on careful histological examination and immunohistochemical markers.
46. THE FINGERPRINT PATTERN OF CD34 IN NEUROFIBROMA D. Ryan and G. Wright Gold Coast University Hospital, Pathology Queensland Background: The histological features of desmoplastic melanoma and neurofibroma can be similar in many instances. The unique fingerprint staining pattern of CD34 may aid in making the correct diagnosis. Case: A 64 year old Caucasian male with history of neurofibromatosis had a pigmented skin lesion excised from his medial left clavicle. The histology showed a dermal spindled cell neoplasm with crowding of melanocytes at the dermoepidermal junction. The lesion was positive for S100 and negative for HMB45, Melan-A, keratin and SMA. A CD34 stain was performed and was diffusely positive throughout the lesion. The positive staining was seen between the collagen bundles in a curvilinear configuration with an appearance resembling a fingerprint pattern. Discussion: In normal skin, CD34 reactivity is found in blood endothelial cells, in interstitial and perivascular spindle-shaped and dendritic cells of the reticular dermis, in elongated cells around the midportion of the hair follicles and in spindle cells around the secretory coils of the eccrine sweat glands. There are numerous cutaneous lesions which show positive CD34 staining including but not limited to DFSP, acral superficial fibromyxoma, solitary fibrous tumour, schwannoma and blue nevi. However the CD34 fingerprint staining pattern is believed to be unique to neurofibroma, perineuroma and DFSP. There is uncertainty as to what the positive labelling is within these lesions which creates the fingerprint pattern. It is postulated that it is positive staining of the endoneurial fibroblasts or perineurial-like cells. In contrast to the fingerprint pattern seen in neurofibromas, the CD34 in desmoplastic melanomas is rarely positive and is often patchy when it is. This case demonstrates the challenge in making the distinction between desmoplastic melanoma and neurofibroma due to their similar histological and immunohistochemical profile and the use of CD34 stain as a potential diagnostic tool. Conclusion: In the appropriate clinical context with supporting histology and immunohistochemistry the CD34 stain can be useful in making the distinction between desmoplastic melanoma and neurofibroma. 47. PRIMARY CUTANEOUS EWING’S SARCOMA J. Saab, K. Nicoll and L. Santos Department of Anatomical Pathology, Liverpool Hospital, NSW
Pathology (2015), 47(S1)
The Ewing’s sarcoma breakpoint region 1 gene (EWSR1, chromosome 22q12) is ubiquitously expressed in human cells but the function of its encoded protein has not yet been elucidated. Rearrangements involving EWSR1 were first described in Ewing sarcoma/peripheral neuroectodermal tumours (PNET) and are now seen in a variety of soft tissue tumours. Most Ewing’s sarcoma cases involve fusion with FLI1, with a minority involving ERG and rarely ETV1, ETV4 and FEV genes amongst others. Cutaneous primary presentation of Ewing’s sarcoma is rare and most cases possess the classic FLI1 t(11;22). Careful clinical and histological examination is required to exclude both a deep-seated primary malignancy and the differential list of small round blue cell tumours. We present a case of primary cutaneous Ewing’s sarcoma arising as nodule in the left upper back of a 14 year old male. Histological and immunohistochemical features were highly suggestive of a Ewing’s sarcoma/PNET. Fluorescence in-situ hybridisation showed a EWSR1 gene rearrangement confirming the tumour belonged to the Ewing’s sarcoma family. However the translocation did not involve the common FLI1 or ERG translocation partners, implying possession of the rarer translocation partners which are not routinely assayed in our local diagnostic laboratory. The patient went on to have post-resection chemotherapy and follow up radiology ten months later showed absence of recurrent or metastatic disease.
48. AN UNUSUAL PRESENTATION OF ANGIOMATOID FIBROUS HISTIOCYTOMA (AFH) Laveniya Satgunaseelan, Mark Wilsher, Fiona Maclean and Fiona Bonar Douglass Hanly Moir, Sydney, Australia AFH accounts for 0.3% of all soft tissue tumours and typically affects the extremities of children and young adults. Classically, microscopically, fascicles and sheets of oval to spindle cells, pseudovascular spaces, haemorrhage and a fibrous pseudocapsule rimmed by a lymphocytic infiltrate are noted. However, some cases lack these typical features, often bearing a striking resemblance to organising haematoma. Recently, cytogenetic analysis of AFH has shown specific translocations involving the EWSR1 and FUS genes. We document a seventy-one year old man who presented with a recurrent lesion of the left triceps muscle, six years after surgical excision. The radiology, morphology and immunohistochemical profile (EMA, desmin negative) of the initial lesion were those of an organising haematoma. (The lesion was completely embedded). It’s true nature was only revealed at recurrence, where characteristic histological and immunohistochemical features of AFH were noted, prompting cytogenetic evaluation of both lesions. The EWSR1 rearrangement was present in the initial and recurrent lesion. Therefore, whilst morphological and immunohistochemical evidence of AFH were not present initially, recent cytogenetic advances have enabled confirmation of AFH at that time. This case illustrates the utility of cytogenetic testing in the diagnosis of AFH where the lesion deviates from the classical histological appearance. This possibility should be considered in haematomas in the absence of a specific cause at any age. References 1. Bohman S, Goldblum JR, Rubin BP, et al. Angiomatoid fibrous histiocytoma: an expansion of the clinical and histological spectrum. Pathology 2014; 46: 199–204. 2. Thway K. Angiomatoid fibrous histiocytoma: A review with recent genetic findings. Arch Pathol Lab Med 2008; 132: 273–7.
Copyright © Royal College of pathologists of Australasia. Unauthorized reproduction of this article is prohibited.
PATHOLOGY 2015 ABSTRACT SUPPLEMENT
Conclusion: 1. Mycobacterium avium-intracellulare infection presenting as bowel perforation is uncommon. 2. The two main histological differentials to consider in the small bowel are Whipple’s disease and signet ring cell carcinoma. 3. The Tropheryma whippleii organisms are non acid-fast and gram positive on histochemical staining. PCR is also useful to confirm the diagnosis. 4. The distinction from a carcinoma can be based on careful histological examination and immunohistochemical markers.
46. THE FINGERPRINT PATTERN OF CD34 IN NEUROFIBROMA D. Ryan and G. Wright Gold Coast University Hospital, Pathology Queensland Background: The histological features of desmoplastic melanoma and neurofibroma can be similar in many instances. The unique fingerprint staining pattern of CD34 may aid in making the correct diagnosis. Case: A 64 year old Caucasian male with history of neurofibromatosis had a pigmented skin lesion excised from his medial left clavicle. The histology showed a dermal spindled cell neoplasm with crowding of melanocytes at the dermoepidermal junction. The lesion was positive for S100 and negative for HMB45, Melan-A, keratin and SMA. A CD34 stain was performed and was diffusely positive throughout the lesion. The positive staining was seen between the collagen bundles in a curvilinear configuration with an appearance resembling a fingerprint pattern. Discussion: In normal skin, CD34 reactivity is found in blood endothelial cells, in interstitial and perivascular spindle-shaped and dendritic cells of the reticular dermis, in elongated cells around the midportion of the hair follicles and in spindle cells around the secretory coils of the eccrine sweat glands. There are numerous cutaneous lesions which show positive CD34 staining including but not limited to DFSP, acral superficial fibromyxoma, solitary fibrous tumour, schwannoma and blue nevi. However the CD34 fingerprint staining pattern is believed to be unique to neurofibroma, perineuroma and DFSP. There is uncertainty as to what the positive labelling is within these lesions which creates the fingerprint pattern. It is postulated that it is positive staining of the endoneurial fibroblasts or perineurial-like cells. In contrast to the fingerprint pattern seen in neurofibromas, the CD34 in desmoplastic melanomas is rarely positive and is often patchy when it is. This case demonstrates the challenge in making the distinction between desmoplastic melanoma and neurofibroma due to their similar histological and immunohistochemical profile and the use of CD34 stain as a potential diagnostic tool. Conclusion: In the appropriate clinical context with supporting histology and immunohistochemistry the CD34 stain can be useful in making the distinction between desmoplastic melanoma and neurofibroma. 47. PRIMARY CUTANEOUS EWING’S SARCOMA J. Saab, K. Nicoll and L. Santos Department of Anatomical Pathology, Liverpool Hospital, NSW
Pathology (2015), 47(S1)
The Ewing’s sarcoma breakpoint region 1 gene (EWSR1, chromosome 22q12) is ubiquitously expressed in human cells but the function of its encoded protein has not yet been elucidated. Rearrangements involving EWSR1 were first described in Ewing sarcoma/peripheral neuroectodermal tumours (PNET) and are now seen in a variety of soft tissue tumours. Most Ewing’s sarcoma cases involve fusion with FLI1, with a minority involving ERG and rarely ETV1, ETV4 and FEV genes amongst others. Cutaneous primary presentation of Ewing’s sarcoma is rare and most cases possess the classic FLI1 t(11;22). Careful clinical and histological examination is required to exclude both a deep-seated primary malignancy and the differential list of small round blue cell tumours. We present a case of primary cutaneous Ewing’s sarcoma arising as nodule in the left upper back of a 14 year old male. Histological and immunohistochemical features were highly suggestive of a Ewing’s sarcoma/PNET. Fluorescence in-situ hybridisation showed a EWSR1 gene rearrangement confirming the tumour belonged to the Ewing’s sarcoma family. However the translocation did not involve the common FLI1 or ERG translocation partners, implying possession of the rarer translocation partners which are not routinely assayed in our local diagnostic laboratory. The patient went on to have post-resection chemotherapy and follow up radiology ten months later showed absence of recurrent or metastatic disease.
48. AN UNUSUAL PRESENTATION OF ANGIOMATOID FIBROUS HISTIOCYTOMA (AFH) Laveniya Satgunaseelan, Mark Wilsher, Fiona Maclean and Fiona Bonar Douglass Hanly Moir, Sydney, Australia AFH accounts for 0.3% of all soft tissue tumours and typically affects the extremities of children and young adults. Classically, microscopically, fascicles and sheets of oval to spindle cells, pseudovascular spaces, haemorrhage and a fibrous pseudocapsule rimmed by a lymphocytic infiltrate are noted. However, some cases lack these typical features, often bearing a striking resemblance to organising haematoma. Recently, cytogenetic analysis of AFH has shown specific translocations involving the EWSR1 and FUS genes. We document a seventy-one year old man who presented with a recurrent lesion of the left triceps muscle, six years after surgical excision. The radiology, morphology and immunohistochemical profile (EMA, desmin negative) of the initial lesion were those of an organising haematoma. (The lesion was completely embedded). It’s true nature was only revealed at recurrence, where characteristic histological and immunohistochemical features of AFH were noted, prompting cytogenetic evaluation of both lesions. The EWSR1 rearrangement was present in the initial and recurrent lesion. Therefore, whilst morphological and immunohistochemical evidence of AFH were not present initially, recent cytogenetic advances have enabled confirmation of AFH at that time. This case illustrates the utility of cytogenetic testing in the diagnosis of AFH where the lesion deviates from the classical histological appearance. This possibility should be considered in haematomas in the absence of a specific cause at any age. References 1. Bohman S, Goldblum JR, Rubin BP, et al. Angiomatoid fibrous histiocytoma: an expansion of the clinical and histological spectrum. Pathology 2014; 46: 199–204. 2. Thway K. Angiomatoid fibrous histiocytoma: A review with recent genetic findings. Arch Pathol Lab Med 2008; 132: 273–7.
Copyright © Royal College of pathologists of Australasia. Unauthorized reproduction of this article is prohibited.