Superficial CD34-positive fibroblastic tumor in the forearm of a middle-aged patient: A newly described, rare soft-tissue tumor

A case of superficial CD34 positive fibroblastic tumor: Diagnostic challenges and pitfalls

ABSTRACT

Superficial CD34 positive fibroblastic tumor (SCPFT) is a recently described soft tissue tumor of intermediate grade with predilection for subcutaneous and superficial fascial planes. Morphological diagnosis of these tumors can be challenging because of overlapping features with other benign and malignant soft tissue tumors of fibroblastic and myofibroblastic origin. A middle-aged man came with a subcutaneous mass in the left thigh. Microscopic examination showed features of an SCPFT comprised of a circumscribed spindle cell tumor with focal striking pleomorphism and bizarre hyperchromatic nuclei. Immunohistochemically (IHC), the tumor cells showed diffuse positivity for CD34 and focally for cytokeratin. Diagnosis of SCPFT on the basis of morphology alone can be challenging. A constellation of clinicoradiological profiles, IHC features, and sometimes molecular studies clinch the definitive diagnosis which can be helpful in avoiding overtreatment and chemotherapy. Here we highlight the diagnostic challenges and pitfalls in a case of SCPFT.

Superficial CD34+ fibroblastic tumor with focal atypical presentation: A case report

Superficial CD34+ fibroblastic tumors (SCPFTs) are rare mesenchymal tumors with distinct morphological features. Although several cases of SCPFT have been reported, a comprehensive understanding of its clinical and biological features necessitates the inclusion of additional cases. The current study presents a case of SCPFT, where morphological observations, immunohistochemical staining and fluorescence in situ hybridization (FISH) were performed. Immunohistochemistry revealed diffuse CD34 expression and integrase interactor 1 expression, whilst FISH indicated rearrangement of the PR/SET domain 10 gene. Microscopic assessment demonstrated typical SCPFT pathology, with a focal nodular region showing a high Ki-67 index, suggesting heterogeneity and the potential for local recurrence. The present study also briefly reviews the differential diagnosis of tumors with morphological similarities. It was found that the precise diagnosis of SCPFT relies on the distinctive pathological features, the use of immunohistochemical markers, including CD34 staining, and the differentiation from similar histological lesions.

Superficial CD34-Positive Fibroblastic Tumor: Two Case Reports

Superficial CD34-positive fibroblastic tumor (SCPFT) is a recently described disease entity characterized by marked nuclear pleomorphism, low mitotic count, and diffuse CD34 positivity. It is a rare, distinctive, low-grade fibroblastic neoplasm. To date, only 44 cases have been reported in the English-language literature. Herein, we report two cases of SCPFT involving a 48-year-old male and a 22-year-old male with superficial tumors on the right and left thighs, respectively. Excision was performed in both cases. Histologically, both tumors showed spindle-to-epithelioid cells arranged in fascicular or sheet-like patterns. Most cells displayed granular or eosinophilic glassy cytoplasm, marked nuclear pleomorphism, and a low mitotic rate. On immunohistochemical staining, tumor cells were diffusely positive for CD34 and negative for S100 protein, smooth muscle actin, and desmin. After wide excision, neither patient experienced recurrence or metastasis after 16 months and 11 months of clinical follow-up, respectively. To the best of our knowledge, these are the first two cases of SCPFT reported in Korea. We believe these case reports would contribute to the clinicopathological understanding of SCPFT and assist clinicians in differentiating this tumor from other superficial soft tissue neoplasms.

Fine needle aspiration cytology of a superficial CD34-positive fibroblastic tumour, including differential diagnoses and recent updates

BACKGROUND

Superficial CD34-positive fibroblastic tumor is recognized as a distinct tumor of fibroblastic lineage in the recent World Health Organization (WHO) classification of tumors of soft tissues. There is an occasional report on cytomorphologic features of this rare tumor.

CASE REPORT

A 28-year-old male presented with swelling in his left thigh of 3 years duration, that was diagnosed as a pleomorphic sarcoma, elsewhere. Radiological imaging showed a well-defined lesion measuring 2.8 cm along the anteromedial aspect of the left mid-thigh in the subcutaneous location. Review of FNAC smears revealed a hypercellular tumor composed of spindle and pleomorphic cells with fine to more vesicular chromatin, and moderate to abundant granular to characteristic "glassy" cytoplasm including cells showing intranuclear pseudo inclusions, devoid of mitotic figures. Interspersed was pink stroma and several inflammatory cells including lymphocytes. Immunohistochemically, tumor cells were diffusely positive for CD34 and focally for AE1/AE3. A diagnosis of superficial CD34-positive fibroblastic tumor was finally offered.

CONCLUSIONS

This constitutes one of the first reports of cytomorphologic features of Superficial CD34-positive fibroblastic tumor. Its differential diagnoses, molecular updates and treatment-associated implications are discussed herewith.

Superficial CD34-positive fibroblastic tumor (SCPFT): A review of pathological and clinical features

Superficial CD34-positive fibroblastic tumor (SCPFT) is a recently described rare mesenchymal tumor of borderline malignancy. It generally involves superficial soft tissue, with a predilection to the lower extremities. Microscopically this tumor is characterized by a fascicular and storiform growth pattern, spindled to epithelioid cells, nuclear atypia with pleomorphism, and eosinophilic granular, and fibrillar to glassy cytoplasm. Strong diffuse immunoreactivity for CD34 is very characteristic of this entity. Due to under-recognition, this tumor is generally underreported. Additionally, cases of recurrence are rarely reported in the literature. We will comprehensively review the English language literature on all reported cases of SCPFT, with emphasis on recurrence.

Superficial CD34-Positive Fibroblastic Tumor on the Chest Wall of an 8-Year-Old Girl: A Case Report and Literature Review

This study reports a case of superficial CD34-positive fibroblastic tumor (SCPFT) in a child and analyze the major known clinicopathological features of SCPFT and other skin mesenchymal tumors, contributing to an accurate diagnosis of this rare disease. We summarize the clinicopathologic features of an 8-year-old girl who was diagnosed with SCPFT and 46 previously reported SCPFT cases. Post-operative histopathologic examination of the current case showed the tumor lesion was well-circumscribed; tumor cells were spindled-to-polygonal with a fascicular pattern; most nuclei displayed hyperchromasia and low mitotic rate; intranuclear pseudoinclusions could be found; and abundant eosinophilic cytoplasm and partial myxoid stroma were observed. Immunohistochemistry revealed strong and diffuse CD34-positivity, vimentin staining positively but no S-100, SMA, NSE, CD31, desmin, cytokeratin, STAT6, β-catenin, MDM2, or ERG expression. The Ki-67 and CD68 labeling indexes were approximately 1%. There were no rearrangements of PDGFB or PRDM10 tested by FISH. After surgical resection, the patient had no signs of recurrence or metastasis at a 6-month follow-up. The present case is the first that describes SCPFT in children and has significant clinical implications. SCPFT should be differentiated from other skin mesenchymal tumors. The presented compilation of all so far published SCPFT cases will help in diagnosing successfully SCPFT and increasing awareness of this tumor to guide clinical practice.

Clinicopathological features of superficial CD34-positive fibroblastic tumor

BACKGROUND

Superficial CD34-positive fibroblastoma (SCPFT) is a newly discovered mesenchymal tumor characterized by high polymorphism, low mitotic rate, and diffuse CD34-positive reactions.

AIM

To further determine the clinicopathological features of SCPFT.

METHODS

We retrospectively analyzed the clinicopathological data, immunohistochemistry results, and differential diagnoses of four patients with SCPFT and performed a literature review. Relevant fusion genes were also detected.

RESULTS

The tumors were all located in the lower extremities and presented as slow-growing painless masses located in the dermis and subcutaneous tissue. Microscopically, the tumors were composed of spindle-shaped to epithelioid cells with scattered abnormal and pleomorphic nuclei on a fibrous or fibromyxoid background. Necrosis was not found in the tumor tissues, and mitotic figures were rare. Immunohistochemically, the tumor cells were strongly positive for vimentin and CD34, and CKpan showed focal positivity in two tumors. All four patients were followed (13-57 mo, mean 35 mo), and one patient experienced local recurrence.

CONCLUSION

SCPFT is a newly discovered borderline mesenchymal tumor that can locally recur or even metastasize. Familiarity with its clinicopathological features will help avoid confusion with skin mesenchymal tumors with similar features.