Atypical fibroxanthoma of the cheek in an elderly patient: a case report and literature review

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Arch Craniofac Surg. 2026;27(4):196-200

Publication date (electronic) : 2026 June 26

doi : https://doi.org/10.7181/acfs.2026.0019

Sae Hwi Ki^,1,2, Gun Hee Lee¹, Do Hyuk Chung¹

¹Department of Plastic and Reconstructive Surgery, Inha University Hospital, Incheon, Korea

²Department of Plastic and Reconstructive Surgery, Inha University School of Medicine, Incheon, Korea

Correspondence: Sae Hwi Ki Department of Plastic and Reconstructive Surgery, Inha University School of Medicine, 27 Inhang-ro, Jung-gu, Incheon 22332, Korea E-mail: mdki1967@gmail.com

Received 2026 January 15; Revised 2026 March 10; Accepted 2026 May 13.

Abstract

INTRODUCTION

Atypical fibroxanthoma (AFX) is an exceptionally rare malignant cutaneous tumor that typically arises on chronically sun-exposed areas, particularly in elderly individuals. Clinically, AFX presents as a firm, flesh-colored to erythematous nodule that may show ulceration or crusting. Despite its relatively slow growth as compared to other high-grade skin cancers, AFX remains a malignant tumor with the potential for local recurrence and metastasis in uncommon cases [1,2]. AFX is a type of fibrohistiocytic tumor with mesenchymal origin, typically confined to the dermis. Although AFX overlaps histologically with various fibrohistiocytic and spindle-cell tumors, its diagnosis is often challenging because of the absence of universally accepted diagnostic criteria and the frequent presence of nonspecific biopsy findings. Indeed, AFX represents only 0.24% of 42,000 cutaneous malignancies, underscoring its extreme rarity and the significant diagnostic uncertainty that often accompanies its evaluation [3]. Consequently, AFX is frequently misidentified as benign lesions or confused with more aggressive neoplasms such as spindle cell squamous cell carcinoma, malignant melanoma, and undifferentiated pleomorphic sarcoma. Accurate distinction from these entities is essential because prognosis and treatment strategies differ substantially [4]. Given this combination of low prevalence, malignant potential, and diagnostic ambiguity, each well- characterized case of AFX provides meaningful clinical insight. This paper reports a rare case of AFX occurring on the left cheek of a 90-year-old woman, in whom the initial biopsy findings were inconclusive. This case highlights the importance of maintaining suspicion for AFX even in atypical clinical contexts and helps improve the diagnostic accuracy for this uncommon tumor.

CASE REPORT

A 90-year-old woman was referred to the Department of Plastic and Reconstructive Surgery after a dermatologic evaluation for a nodule on the left cheek. Several weeks earlier, a local dermatology clinic had performed a biopsy, which revealed spindle cell proliferation without a definitive diagnosis. An additional punch biopsy was subsequently performed, which confirmed AFX. The lesion measured 2.5×1.2 cm and appeared crusted, ulcerative, and erythematous (Fig. 1). The patient denied pain or pus discharge. Her medical history was notable only for hypertension and diabetes mellitus type 2. Preoperative magnetic resonance imaging (MRI) revealed a 0.9 cm enhancing ovoid mass within the skin and subcutaneous fat layer of the left cheek, without cervical lymphadenopathy (Fig. 2). A full-thickness skin graft after wide excision and subsequent histological examination was planned. A skin incision line with a 1 cm safety margin was designed after infiltrating the area with local anesthesia (Fig. 3A). The tumor was completely excised without complications, resulting in a 2.5×3.5 cm defect. Intraoperative frozen-section analysis confirmed the excision with negative margins. A full-thickness skin graft was harvested from the left supraclavicular area and secured with a tie-over dressing (Fig. 3B). A permanent histopathology examination reconfirmed the diagnosis of AFX (Fig. 4). At 10 days postoperatively, the graft showed a stable take without complications (Fig. 5A). MRI performed at 1-year follow-up showed no evidence of regional lymph node metastasis, and the patient remained free of recurrence. The grafted contour was well maintained without noticeable deformity (Fig. 5B).

Fig. 1.

Preoperative photograph. A 90-year-old woman presented with a mass on the left cheek.

Fig. 2.

Preoperative radiological examination. A 0.9 cm-sized, T2 isointense, enhancing ovoid mass in the skin and subcutaneous fat layer of the left cheek on magnetic resonance imaging.

Fig. 3.

Intraoperative photographs. (A) Design for wide excision with a 1 cm safety margin. (B) Immediate postoperative photograph after full-thickness skin graft with tie-over dressing in place.

Fig. 4.

Histopathological examination. (A) Spindle cell proliferation consistent with atypical fibroxanthoma (hematoxylin & eosin, ×200). (B) Giant cells and frequent mitotic figures seen at ×400 magnification.

Fig. 5.

Follow-up photograph. (A) At 10 days postoperatively, the graft demonstrated complete take without complications. (B) Photograph at 1 year postoperatively, no recurrence was observed, and the contour was well maintained.

LITERATURE REVIEW

AFX is an uncommon cutaneous malignancy of fibroblastic origin, the rarity of which has contributed to the absence of universally accepted diagnostic criteria. In elderly patients, AFX predominantly arises in sun-exposed regions such as the head and neck. Most cases occur in individuals over 70 years of age and the disease often presents as rapidly growing erythematous or ulcerated nodules in these areas, frequently mimicking other skin cancers [5]. Although AFX typically develops in ultraviolet-exposed sites, rare occurrences in areas with minimal sun exposure, such as the dorsum of the foot, have been documented, making clinical suspicion even more challenging [6]. Considering this wide clinical variability, reliance on a physical examination alone often results in diagnostic uncertainty. This diagnostic ambiguity is particularly relevant in elderly patients, in whom benign and malignant cutaneous tumors frequently coexist and often exhibit overlapping clinical features.

A definitive diagnosis of AFX relies on histopathologic examination. Although AFX shares many microscopic features with undifferentiated pleomorphic sarcoma, it differs by being confined to the dermis without deep invasion. Biopsy specimens typically reveal spindled and pleomorphic tumor cells, often accompanied by multinucleated giant cells. Despite the high proliferative activity, histologic features associated with more aggressive malignancies, such as necrosis, lymphovascular invasion, or perineural infiltration, are generally absent. Immunohistochemistry provides additional diagnostic value, particularly in differentiating AFX from spindle cell squamous cell carcinoma or desmoplastic melanoma. AFX frequently shows positivity for markers such as vimentin, α1-antitrypsin, factor XIII, cluster of differentiation (CD)68, CD10, and smooth muscle actin (SMA), whereas melanocytic markers including S-100 and HMB-45 remain negative [7-9].

Surgical excision remains the mainstay of treatment for AFX. Although favorable outcomes with radiation therapy have been reported, further evidence is required before it can be recommended as a standard treatment modality [10]. Currently, wide local excision and Mohs micrographic surgery are the most commonly employed surgical approaches. Mohs surgery offers superior margin control and has been associated with lower recurrence rates compared with conventional excision; however, its longer operative time and resource requirements may limit its use depending on the clinical context [11,12].

Prognosis of AFX is generally favorable after complete surgical removal; however, local recurrence and metastasis have been reported. In a systematic review and meta-analysis, Mohs micrographic surgery was associated with a lower local recurrence rate than wide local excision (2.0% vs. 8.7%), while metastatic events were uncommon in both groups (1.9% vs. 1.0%) [12]. In addition, a large single-institution series reported excellent local control with a median 1.0 cm excision margin and no disease-specific mortality [3]. These findings emphasize that adequate excision with reliable margin control is the most important determinant of outcome in AFX.

DISCUSSION

Clinically, AFX often mimics common cutaneous malignancies on sun-damaged facial skin, including squamous cell carcinoma, basal cell carcinoma, and amelanotic melanoma, because it may present as a rapidly enlarging, ulcerated erythematous nodule. Therefore, clinicopathologic correlation and immunohistochemistry are crucial for diagnosis: spindle cell squamous cell carcinoma typically shows cytokeratin positivity, desmoplastic melanoma shows melanocytic marker positivity (e.g., S-100), whereas AFX is usually negative for cytokeratin and melanocytic markers and often shows CD10 positivity [4,7-9]. Distinguishing AFX from pleomorphic dermal sarcoma is important because tumors with deeper extension (beyond the dermis) or high-risk histologic features, such as necrosis or perineural or lymphovascular invasion, are more likely to behave aggressively and may require more intensive surveillance [4].

The presentation of this case is clinically significant because AFX is a rare malignancy, and establishing the diagnosis itself is meaningful. Moreover, AFX presents substantial diagnostic challenges due to its considerable histopathologic overlap with other cutaneous malignancies, making the diagnostic process particularly important. This case involved a lesion arising on the cheek, a sun-exposed area consistent with a typical predilection site of AFX in the head and neck region. However, facial neoplasms often present with nonspecific or overlapping features, making clinical findings alone insufficient for establishing a definitive diagnosis [13,14]. In the present case, the immunohistochemical profile—showing positivity for CD10 and SMA and negativity for S-100—was consistent with the diagnosis of AFX and played a crucial role in confirming the final diagnosis after the initial biopsy yielded inconclusive findings.

The choice of surgical management in this case warrants further discussion. Wide local excision with intraoperative frozen-section margin assessment was selected after considering the patient’s advanced age, lesion size, and the need for reliable oncologic control. In reference to a recent publication with excellent local control, the safety margin was set at 1 cm [3]. In addition, intraoperative frozen-section analysis was performed to confirm margin negativity and to compensate for not using Mohs surgery. Although Mohs micrographic surgery has been associated with lower recurrence rates and superior margin control, its longer operative time and resource requirements may limit its practicality in certain clinical settings [11,12]. When complete margin assessment is not available, recent probabilistic modeling suggests that larger tumors may require wider excision margins [11]. In the present case, frozen-section analysis provided real-time margin confirmation, enabling immediate reconstruction with a full-thickness skin graft while maintaining acceptable aesthetic outcomes.

Although most AFX behave in an indolent manner after complete excision, local recurrence and metastasis have been reported. In the systematic review and meta-analysis, metastatic rates were approximately 1.0% to 1.9% after surgery, and wide local excision showed a higher recurrence rate than Mohs micrographic surgery [12]. Importantly, metastatic or repeatedly recurrent cases often show deeper extension or other high-risk histologic features and may represent tumors along the spectrum toward pleomorphic dermal sarcoma [4,15]. Therefore, careful clinical surveillance is warranted, particularly in elderly patients. In the present case, follow-up MRI performed 1 year postoperatively demonstrated no evidence of local recurrence or regional metastasis.

The report of this case is considered significant because AFX presents a rare malignancy, and establishing the diagnosis itself is of clinical importance. Given the rarity of AFX and the limited number of well-documented craniofacial cases in the literature, detailed case reports remain valuable for improving diagnostic accuracy and for guiding practical surgical decision-making. This report may aid clinicians in distinguishing AFX from other spindle-cell tumors and in selecting an appropriate margin-control strategy, particularly in old patients.

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