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. 2024 Aug;36(4):209-214.
doi: 10.5021/ad.23.135.

Intralesional Methotrexate Injection for the Treatment of Epithelial Crateriform Tumor

Jun Hyuk Cho  1 , Hyun Mo Lee  1 , Yoon Jae Kim  1 , Dai Hyun Kim  1 , Hyo Hyun Ahn  1 , Soo Hong Seo  2
Affiliations

Intralesional Methotrexate Injection for the Treatment of Epithelial Crateriform Tumor

Jun Hyuk Cho et al. Ann Dermatol. 2024 Aug.

Abstract

Background: Intralesional methotrexate injection (IL-MTX) is an appropriate strategy for treating epithelial crateriform tumors (ECTs) when surgical excision can result in functional or cosmetic defects; however, not all ECTs are responsive to this treatment.

Objective: This study aimed to evaluate the effectiveness of IL-MTX for ECTs and to determine the differences in clinical response according to the pathological features.

Methods: The medical records of patients treated with IL-MTX for their ECTs were retrospectively reviewed. Effectiveness was evaluated in terms of size reduction and flattening.

Results: Twenty-five cases of ECTs with biopsy were included in this study. Eight cases of keratoacanthoma (KA) and 15 cases of squamous cell carcinoma (SCC) were identified, but 2 cases could not be clearly distinguished. Seventeen patients (68%) showed a response after injection, and response rate in KA and SCC were 75% (6/8) and 60% (9/15), respectively. Nine patients showed complete resolution with IL-MTX. Patients received 3 injections, and regression was observed in 7.56 weeks after the first injection. According to histopathological results, patients with KA and SCC received 2 and 3.33 injections, respectively, and complete resolution was observed after 7 and 7.67 weeks, respectively.

Conclusion: IL-MTX is safe and effective, and could be considered as a useful non-surgical treatment option for ECTs. Both KA and crateriform SCC showed good response; However, KA showed a better response.

Keywords: Keratoacanthoma; Methotrexate; Squamous cell carcinoma.

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Conflict of interest statement

The authors have nothing to disclose.

Figures

Fig. 1
Fig. 1. Histopathologic findings and clinical response of keratoacanthoma completely resolved through intralesional methotrexate injection itself. (A) Clinical resolution after 2 injections. (B) Initial biopsy shows large pale pink cell proliferation with a glassy appearance and symmetrical crateriform architecture with peripheral collarette (hematoxylin and eosin, ×40).
Fig. 2
Fig. 2. Histopathologic findings and clinical response of well differentiated squamous cell carcinoma completely resolved through intralesional methotrexate injection itself. (A) Clinical resolution after 3 injections. (B) Initial biopsy shows tumor nests of atypical keratinocytes on whole lesion with less large pale pink cells compared to keratoacanthoma (hematoxylin and eosin, ×40).
Fig. 3
Fig. 3. Moderately differentiated squamous cell carcinoma completely resolved through intralesional methotrexate administration itself. (A) Complete resolution after 6 injections. (B) Initial biopsy shows pleomorphic atypical tumor nests invading deep dermal layer (H&E, ×100). (C) Complete resolution was pathologically confirmed after excision and cytologic atypia was not found in epithelial component (H&E, ×40).
H&E: hematoxylin and eosin.
See this image and copyright information in PMC

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