| Abstract|| |
Superficial CD34-positive fibroblastic tumor is a recently described soft-tissue tumor entity. A 48 year-old-male presented with a gradually increasing soft-tissue mass in his right forearm of 2 years' duration, along with multiple subcutaneous soft-tissue nodular lesions, and reminiscent of lipomas over his body. He underwent a wide excision of his forearm mass. Microscopic sections showed a circumscribed tumor in the dermis and subcutaneous fat, composed of spindle cells, inflammatory cells, including lymphocytes, plasma cells, and eosinophils, along with interspersed markedly pleomorphic giant cells containing moderate-to-abundant “glassy” cytoplasm, vesicular nuclei, exhibiting prominent nucleoli, and intranuclear pseudoinclusions. There were no significant mitotic figures, areas of hemorrhage, necrosis, or pigment histiocytes. By immunohistochemistry, the tumor cells were diffusely positive for CD34 while negative for cytokeratin (CK), pan CK (AE1/AE3), S100 protein, CD30, and CD31. MIB1/Ki-67 was low and highlighted 4%–5% tumor nuclei. Diagnosis of superficial CD34-positive fibroblastic tumor was offered. Sections from the various resection margins were free of tumor. Postresection, the patient is alive with no evidence of disease for the past 8 months. This constitutes as one of the first case reports of this rare tumor entity from our country. Its diagnostic and treatment implications are discussed herewith.
Keywords: CD34, myxoinflammatory fibroblastic sarcoma, newly described soft-tissue tumors, superficial CD34-positive fibroblastic tumor
|How to cite this article:|
Rekhi B, Banerjee D, Gala K, Gulia A. Superficial CD34-positive fibroblastic tumor in the forearm of a middle-aged patient: A newly described, rare soft-tissue tumor. Indian J Pathol Microbiol 2018;61:421-4
|How to cite this URL:|
Rekhi B, Banerjee D, Gala K, Gulia A. Superficial CD34-positive fibroblastic tumor in the forearm of a middle-aged patient: A newly described, rare soft-tissue tumor. Indian J Pathol Microbiol [serial online] 2018 [cited 2020 Feb 19];61:421-4. Available from: http://www.ijpmonline.org/text.asp?2018/61/3/421/236600
| Introduction|| |
Superficial CD34-positive fibroblastic tumor is a relatively recently described low-grade mesenchymal tumor of intermediate malignant potential (rarely metastatic) by Carter et al. It is characterized by certain histopathologic features that differentiate this tumor from its closest mimics, namely, myxoinflammatory fibroblastic sarcoma and malignant fibrous histiocytoma. Herein, we report one of the first such cases from our country.
| Case Report|| |
A 48-year-old-male presented with a gradually increasing soft-tissue mass in his right forearm of 10 months duration. In addition, he had multiple subcutaneous soft-tissue nodular lesions and reminiscent of lipomas over his body.
During his recent clinical examination, a lesion measuring 3 cm × 3 cm, soft to firm in consistency was noted in the ventral aspect of the lower one-third of his right forearm. He underwent radiographic imaging, followed by biopsy and tumor resection. His initial biopsy was reported elsewhere as a synovial sarcoma.
Plain radiograph revealed well-defined, soft-tissue opacity, involving the skin and subcutaneous tissues, in the distal aspect of his right forearm.
Magnetic resonance imaging showed a well-defined, altered signal intensity lesion over the volar aspect of his right forearm in the subcutaneous plane, measuring 2 cm × 1.8 cm × 1 cm. The lesion appeared hypointense on T1-weighted and intermediate signal intensity on T2-weighted images and showed homogeneous postcontrast enhancement and restriction diffusion [Figure 1].
|Figure 1: Magnetic resonance imaging showing a well-defined, altered signal intensity lesion over the volar aspect of his right forearm in the subcutaneous plane|
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Grossly, an oriented resection specimen of a soft-tissue tumor mass was received, measuring 5.5 cm × 2.5 cm × 1.5 cm with attached skin. On serial sectioning, a grayish-white, firm, homogeneous tumor was identified, measuring 1 cm × 1 cm × 0.8 cm. It was firm in consistency and homogeneous. There were no areas of hemorrhage and necrosis. The tumor was seen abutting the overlying skin. All the resection margins were more than or equal to 0.5 cm.
Histopathologic sections showed a circumscribed tumor in the dermis and subcutaneous fat, exhibiting polymorphic appearance, including spindle cells, inflammatory cells, comprising lymphocytes, plasma cells, and eosinophils, along with interspersed markedly pleomorphic giant cells containing moderate-to-abundant “glassy” cytoplasm, vesicular nuclei, exhibiting prominent nucleoli, and intranuclear pseudo inclusions. There was an isolate mitotic figure, without any atypical forms. There were no areas of hemorrhage, necrosis, or pigment histiocytes [Figure 2] and [Figure 3].
|Figure 2: Microscopy showing elongate fibroblastic cells with intervening pleomorphic cells, including those containing “glassy” cytoplasm and intranuclear pseudoinclusions (arrowhead) (H and E, ×200)|
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|Figure 3: Several pleomorphic giant cells; cells with “glassy” cytoplasm, along with interspersed inflammatory cells, including eosinophils, lymphocytes, and plasma cells (H and E, ×400)|
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By immunohistochemistry, the tumor cells were diffusely positive for CD34 [Figure 4], while negative for cytokeratin (CK), pan CK (AE1/AE3), S100 protein, CD30, and CD31; the latter antibody marker highlighted the plasma cells. MIB1/Ki-67 was low and highlighted 4%–5% tumor nuclei. All the resection margins were free of tumor.
|Figure 4: Immunohistochemical result. Tumor cells showing diffuse CD34 positivity (3'-3'diaminobenzidine, tetrahydrochloride, ×400)|
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Diagnosis of superficial CD34-positive fibroblastic tumor was offered. Sections from the various resection margins were free of tumor. Postresection, the patient did not receive any adjuvant treatment and is alive with no evidence of disease for the past 8 months.
Fine-needle aspiration cytology from one of the other multiple soft-tissue lesions showed mature adipose tissue fragments against a lipoproteinaceous background, confirming a diagnosis of lipoma/benign lipomatous neoplasm.
| Discussion|| |
After the recent World Health Organization classification of soft-tissue tumors, Carter et al. described another soft-tissue tumor entity, namely, superficial CD34-positive fibroblastic tumor, in the form of 18 cases, predominantly occurring in the superficial aspect of lower extremities of males, with age ranging from 20 to 76 years (median = 38). Subsequently, there have been few documented case reports and another series of 11 such cases, including an occasional case reported from our country.,,, Less than 5 cases of superficial CD34-positive fibroblastic tumor have been reported in the upper extremities, as noted in the present case.,,
Various differential diagnoses considered in the present case were myxofibrosarcoma (myxoid malignant fibrous histiocytoma), hemosiderotic fibrolipomatous tumor, pleomorphic hyalinizing angiectatic tumor (PHAT), and myxoinflammatory fibroblastic sarcoma. Lack of pigment macrophages and adipocytic differentiation ruled out a hemosiderotic fibrolipomatous tumor. Lack of hyalinized and thrombosed blood vessels or stromal hyalinization made the diagnosis of PHAT, less likely. Whereas there were overlapping features with a myxoinflammatory fibroblastic sarcoma and lack of pigment histiocytes, significant myxoid areas, along with the presence of several tumor cells containing characteristic “glassy” cytoplasm, coupled with diffuse immunohistochemical expression of CD34 within the tumor, favored a superficial CD34-positive fibroblastic tumor. Myxoinflammatory fibroblastic sarcomas, including cases with areas of hemosiderotic fibrolipomatous tumors, are characterized by rearrangements of TGFBR3 and MGEA5 genes., Lack of these gene rearrangements in all five tested cases of superficial CD34-positive fibroblastic tumor, in the seminal study of Carter et al., separates this tumor from myxoinflammatory fibroblastic tumor. Due to unavailability of these probes in our laboratory, we could not test our case for these genes, similar to the other recently reported cases series and report.,
Immunohistochemically, apart from consistent CD34 positivity, this tumor is also known to express focal CK expression in 69% cases, a feature that was lacking in this case, but in congruence with another recently reported such case by Wada et al., wherein the investigators also ruled out a possibility of dermatofibrosarcoma protuberans (DFSP) by demonstrating collagen type 1 alpha-1–platelet-derived growth factor beta chain-negative results. Pleomorphic giant cells, as noted in this tumor, are less likely in a case of DFSP unless it coexists with a giant cell fibroblastoma. Aforementioned histopathologic features, along with the absence of pseudolipoblastic cells, were helpful in ruling out a myxofibrosarcoma.
Despite pleomorphic cells, a high-grade pleomorphic sarcoma was ruled out, in view of lack of significant mitotic figures, abnormal forms, and tumor necrosis. This is precisely the reason, this tumor entity assumes importance, as it can be misdiagnosed as a high-grade that happened in this case at the referring hospital. Diagnosis of high-grade sarcoma could have possibly let to adjuvant, toxic treatment and/or a radical excision. Co-existence of lipomas was incidental in the present case. Clinically, these tumors are associated with an indolent behavior. During follow-up (median = 24 months), Carter et al. observed no tumor recurrences in 12 out of their 13 cases. However, one of their cases developed regional lymph node metastasis, wherein the tumor was marginally excised. They recommended inclusion of these tumors into the category of intermediate malignant (rarely metastasizing). The present case is free-of-disease for the past 8 months.
To sum up, this is one of the first reported cases of a superficial CD34-positive fibroblastic tumor from our country. This newly recognized entity seems to expand the histopathologic spectrum of fibroblastic tumors, especially those containing pleomorphic giant cells. It correct identification has significant treatment implications.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
This case was sent for another opinion to Professor Andrew L. Folpe, Mayo Clinic, Rochester, USA, who concurred with the diagnosis. We are very much grateful to him.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Department of Surgical Pathology, Tata Memorial Hospital, Room No. 818, 8th Floor, Annex Building, Dr. E. B. Road, Parel, Mumbai - 400 012, Maharashtra
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4]