Dear editors,
Superficial CD34‐positive fibroblastic tumor (SCPET) is a newly recognized soft tissue tumor characterized by remarkable cellular pleomorphism, rare mitotic counts, and strong CD34 expression. 1 However, cases of this tumor in children are rarely reported, which making the diagnosis extremely difficult. Herein, we describe a young girl with SCPET on the axilla. Through our report, we hope to improve the understanding of SCPET and avoid misdiagnosis.
An 11‐year‐old girl presented with an erythema on the left axilla for 2 years, which was mildly tender after applying pressure on the lesion. Examination detected an irregular erythema on the left axilla with a clear border (Figure 1A). An excisional biopsy was subsequently performed. Routine histopathology revealed a spindle‐cells tumor arranged in fascicles, locating throughout the deep dermis and superficial subcutis (Figure 1B). The tumor cells showed significant pleomorphism while mitoses were rare (Figure 1C). Immunohistochemical findings showed that the tumor cells diffusely and strongly expressed CD34 (Figure 1D). Vimentin staining positively as well. Smooth muscle actin (SMA) was focally positive and Ki‐67 labeling index was approximately 2% (Figure 1E). The tumor cells were negative for S‐100, desmin, EMA, Pan‐Trk, cytokeratin (AE1/AE3). All these results supported the final diagnosis of SCPET on the left axilla. The patient subsequently underwent an expanded excision with negative surgical margins. At 5 months of postoperative follow‐up, no recurrence or metastasis was observed.
FIGURE 1.
(A) An irregular erythema on the left axilla. (B) The tumor in the dermis was composed of spindle cells arranged in fascicles (hematoxylin and eosin staining [HE], original magnification×100). (C) The tumor cells showed nuclear pleomorphism (HE, original magnification×200). Immunohistochemical staining exhibited strong and diffuse expression of CD34 (D) and low Ki‐67 proliferation index (E).
First described in 2014, 2 SCPET is a low‐grade mesenchymal neoplasm with intermediate malignancy that mainly affects adult males. Most of these tumors occur in the lower extremities particularly in the thighs and buttocks. 3 There are only a few cases reported in pediatrics, aged from 8 to 16 years old. The typical lesion appears as a mass ranging in size from 1.5 to 10 cm. Patients usually do not complain any symptom of itching or pain, but a few patients may feel minimal tenderness on palpation. 4 In our case, the child patient presented with an erythema on the axilla, which may indicate dermatologists that single erythema can be the initial manifestation of SCPET.
Histopathologically, SCPET is confined in the deep dermis and superficial subcutis. Tumor cells are composed of spindled to epithelioid cells arranged in fascicles with nuclear pleomorphism, but mitotic counts are extremely rare and no evidence of necrosis. Immunohistochemical features are strong and diffuse expression of CD34, positive vimentin staining, and low Ki‐67 proliferation index. Cytokeratin (AE1/AE3) and S‐100 are partially expressed or totally negative. SCPETs are negative for the expression of SMA, desmin, EMA, HMB‐45, and melan‐A. 3 , 4 Our histological and immunohistochemical characteristics are comparable to prior series. Recently, a retrospective study involving 59 cases exhibited SCPET frequently expressed CADM3 (95%) and WT1 (75%), implying that CADM3 and WT1can act as ancillary markers to assist in diagnosis and discrimination from histological mimics. 5
In conclusion, our case report aims to enrich the existing literature and to aid pediatric dermatologists in the recognition of tumor features, thus providing timely diagnosis and treatment.
CONFLICT OF INTEREST STATEMENT
The authors declare no conflicts of interest.
ETHICS STATEMENT
The patient's mother has given written consent to publish this case details.
DATA AVAILABILITY STATEMENT
Data sharing is not applicable to this article as no new data were created or analyzed in this study.
REFERENCES
- 1. Salah HT, D'Ardis J A, Baek D, Schwartz MR, Ayala AG, Ro JY. Superficial CD34‐positive fibroblastic tumor (SCPFT): A review of pathological and clinical features. Ann Diagn Pathol. 2022;58:151937. [DOI] [PubMed] [Google Scholar]
- 2. Carter JM, Weiss SW, Linos K, DiCaudo DJ, Folpe AL. Superficial CD34‐positive fibroblastic tumor: report of 18 cases of a distinctive low‐grade mesenchymal neoplasm of intermediate (borderline) malignancy. Mod Pathol. 2014;27(2):294‐302. [DOI] [PubMed] [Google Scholar]
- 3. Li Y, Geng Y. Superficial CD34‐positive fibroblastic tumor. J Dtsch Dermatol Ges. 2023;21(1):71‐73. [DOI] [PubMed] [Google Scholar]
- 4. Li SY, Zhang HL, Bai YZ. Superficial CD34‐positive fibroblastic tumor on the chest wall of an 8‐year‐old girl: a case report and literature review. Pediatr Hematol Oncol. 2021;38(6):602‐608. [DOI] [PubMed] [Google Scholar]
- 5. Anderson WJ, Mertens F, Mariño‐Enríquez A, Hornick JL, Fletcher CDM. Superficial CD34‐positive fibroblastic tumor: a clinicopathologic, immunohistochemical, and molecular study of 59 cases. Am J Surg Pathol. 2022;46(10):1329‐1339. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
Data sharing is not applicable to this article as no new data were created or analyzed in this study.