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Trichoblastic carcinoma: A cautionary tale

 Department of Radiation Oncology, Christian Medical College and Hospital, Ludhiana, Punjab, India

Date of Submission05-Jul-2022
Date of Decision06-Jul-2022
Date of Acceptance07-Jul-2022
Date of Web Publication24-Aug-2022

Correspondence Address:
Aprajita Mall,
Department of Radiation Oncology, Christian Medical College and Hospital, Ludhiana, Punjab
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jrcr.jrcr_42_22


Trichoblastic carcinoma is a rare malignant hair follicle tumor. It resembles basal cell carcinoma clinically. However, various studies have emphasized the importance of differentiating between these two cancers since they have a different clinical course, which may affect treatment options and subsequent follow-up plans. Despite its aggressive behavior, there is a lack of uniform consensus on the treatment. We report the case of a 65-year-old woman with trichoblastoma with focal transformation to low-grade trichoblastic carcinoma. This patient underwent surgical excision of the carcinoma, followed by adjuvant radiation therapy in view of residual disease. The patient was disease-free for 3 years. The intent of reporting this case is to help oncologists recognize similar cases and consequently plan the treatment in a way to improve the survival of these patients.

Keywords: Chemotherapy, high-grade carcinoma, radiotherapy, trichoblastoma

How to cite this URL:
Mall A, Kingsley PA, Negi P, Gupta P. Trichoblastic carcinoma: A cautionary tale. J Radiat Cancer Res [Epub ahead of print] [cited 2022 Dec 4]. Available from:

  Introduction Top

Cutaneous adnexal tumors are caused by the morphologic differentiation of primary adnexal structures in the hair follicles, sebaceous glands, apocrine glands, and eccrine glands. Among these, trichoblastic carcinoma is a rare malignant follicular neoplasm, rarely encountered in the clinical setting. It involves the malignant transformation of the trichoblastoma. The naming of trichoblastoma originated from the overarching term “trichoepithelioma” to distinguish a neoplasm with follicular germinative differentiation.[1] Reports of this malignant neoplasm are sparse throughout the literature, and, given its low occurrence rate, the prevalence is difficult to determine. Its presentation is similar to that of other adnexal neoplasms, in that it appears as either a nonspecific flesh-colored papule or nodule or mimics a Basal cell carcinoma (BCC). It resembles basal cell carcinoma clinically, but different studies emphasize the importance of differentiating between these two cancers since they have a different clinical course, which may affect treatment options and follow-up. Trichoblastomas are usually not aggressive, but trichoblastic carcinomas arise from preexisting trichoblastomas and have been linked to basal cell carcinoma. This malignancy seems to show only locally aggressive growth. We report a rare case of trichoblastoma with focal transformation to low-grade trichoblastic carcinoma. This patient underwent surgical excision of the carcinoma, followed by adjuvant radiation therapy in view of residual disease. The patient was disease free for 3 years.

  Case Report Top

A 65-year-old female presented to a local practitioner with nodularity over the posterior aspect of the left ear pinna for the past 5 years. As per the patient, the nodularity was painless, to begin with measuring 2 cm × 2 cm, and later started to progress and attained the size of a lemon and was associated with mild pain. There was no history of bleeding, fever, changes in the overlying skin, or any constitutional symptom. She consulted a general practitioner and underwent an excision of the lesion in November 2018. Histopathological examination suggested basal cell carcinoma. She was then referred to our institution for expert management.

Examination revealed a surgical scar with surrounding beaded pearly white nodularity. The specimen was reviewed and reported as a tumor centered in the dermis composed of nodules, nests, and sheets of basaloid cells showing prominent peripheral palisading separated by a scant amount of fibromyxoid and hyalinized stroma. The tumor cells showed round to oval pleomorphic nuclei, finely clumped chromatin, small nuclei, and scanty to moderate cytoplasm. Focal areas showed an increase in mitotic activity and were reported as trichoblastoma with focal transformation to low-grade trichoblastic carcinoma [Figure 1]. In view of residual disease, the patient was offered adjuvant radiation therapy. The patient was immobilized using an orfit thermoplastic cast and left ear mold and underwent a 3-mm contrast-enhanced computed tomography scan in the supine position with head-and-neck rest and shoulder traction. A 10 cm × 10 cm bolus was used over the left ear pinna placed inside the cast. The dose delivered was - 50.4 Gy/28 F at 1.8Gy/F over 5.3 weeks with a three-dimensional conformal radiotherapy technique. The patient tolerated the treatment well and is on a regular follow-up till date. A written informed consent was obtained from the patient for publication of this case report and any accompanying image.
Figure 1: Photomicrographs of low-grade trichoblastic carcinoma showing a basaloid tumor arranged predominantly in solid nodules and nests without peripheral retraction artifact.(a and b) shows increase in mitotic activity noted (arrows), (c) focal clearing of cells (blue arrows), (d) focal squamous differentiation (red arrows), H and E, ×400

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  Discussion Top

Trichoblastic carcinoma is a rare tumor of the adnexal structures. The first description of a “primary neoplasm of hair matrix” was made in 1962 by Headington and French.[2]

The papillary induction of follicular germ was recognized by Headington and French as a characteristic feature of trichoblastic tumors based on the observation of an intimate association of stroma and epithelium in their specimens.[3] For these reasons, they named this benign neoplasm trichogenic adnexal tumor, and in 1976, they called similar-appearing neoplasms trichoblastomas.[4] The pathogenesis of trichoblastic carcinoma is unknown.[5]

It is important to differentiate it from other malignant tumors due to its aggressive nature. The presentation, differential diagnosis, and treatment of trichoblastic carcinoma are quite complex and controversial with only a few cases being reported in the literature. Clinical identification of this neoplasm is difficult. In 94% of the cases, a diagnosis of basal cell carcinoma is made.[6] Immunostains have been used in a few case reports to help other investigators differentiate this neoplasm from a BCC or trichoepithelioma; however, the results have varied thus far. One case report of an aggressive trichoepithelioma that was later determined to be a trichoblastic carcinoma by Ackerman et al.[1] showed that CD34 stained positively in the tumor stroma, but not in a reference BCC. Kazakov et al.[7] also showed a case with similar histology, which was referred to as a rare biphasic follicular neoplasm resembling trichoblastoma, but with features of malignancy by virtue of infiltrative growth. In addition, Bordelon et al.[8] found that BCL-2 was diffusely positive in BCCs, but was only present at the rim of cells in the tumor lobule of a trichoblastic carcinoma neoplasms, in that it appears as either a nonspecific flesh-colored papule or nodule or mimics a BCC.

Once the diagnosis is made, an extensive clinical workup is needed due to the aggressiveness of the tumor. A thorough clinical examination needs to be undertaken in the presence of clinical signs and symptoms.[9] Low-grade carcinomas are usually locally invasive and aggressive with frequent local relapse. However, this comes from a limited number of cases and no well-documented long-term follow-up.[10] High-grade carcinomas have considerable metastatic potential, particularly in the lung.[2] A close surveillance every 3 months is recommended for high-grade tumors and 6 months for low-grade tumors.[9]

The standard treatment protocol is not established yet; complete surgical excision is considered the treatment of choice to avoid local recurrences.[11] The role of adjuvant radiotherapy has been suggested by some authors.[12] When local or systemic metastasis is present, chemotherapy or radiotherapy can be performed; however, this has not yet been defined.[13]

In reviewing the literature, adjuvant radiation therapy seems to show an additional benefit in cases of high-grade tumors, younger age groups, and infiltrative tumors or with close or positive margins in an attempt to reduce the chances of recurrence.[2] Radiotherapy can be used as an alternative if surgery is not possible. Laffay et al. suggested the use of radiotherapy for aggressive trichoblastic carcinoma, particularly those with tumor diameter >4 cm, deep infiltration, and young age to improve local tumor control.[14] For macroscopic disease, a dose of 70Gy should be delivered. A dose of at least 50 Gy has been reported for the microscopic residual disease.[15]

The role of chemotherapy is considered an option in metastatic trichoblastic carcinoma. Vismodegib is a new chemotherapeutic agent that showed signs of tumor regression, especially in locally advanced and metastatic cases. It is a monoclonal antibody that has an inhibitory action on the sonic hedgehog pathway.[16] Sunitinib is another chemotherapeutic agent that can be used to treat patients with metastatic trichoblastic carcinoma. In one case, partial remission and disease stabilization were observed after 10 months[17] of sunitinib.

We report remarkable survival of 3 years of trichoblastic carcinoma without evidence of recurrent disease. Treatment with surgery, followed by adjuvant radiation therapy, was tolerated relatively well, and probably the reason for better survival outcomes. Given the rarity of trichoblastic carcinoma, this case report will definitely add a much-needed viewpoint to the treating oncologists toward managing similar cases with adjuvant radiation therapy for carefully selected cases.

  Conclusion Top

Trichoblastic carcinoma is a rare and difficult-to-manage malignancy, due to the lack of well-established treatment guidelines. However, in selected cases, complete surgical excision, followed by adjuvant radiation therapy, has been reported to result in improved local control.


We would like to acknowledge Dr. Bhanu Vashishta for helping us with the literature search.

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.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Ackerman AB, Reddy VB, Soyer HP. Neoplasms With Follicular Differentiation. 2nd ed. New York: Ardor Scribendi; 2001. p. 1109.  Back to cited text no. 1
Headington JT, French AJ. Primary neoplasms of the hair follicle. Histogenesis and classification. Arch Dermatol 1962;86:430-41.  Back to cited text no. 2
Rofagha R, Usmani AS, Vadmal M, Hessel AB, Pellegrini AE. Trichoblastic carcinoma: A report of two cases of a deeply infiltrative trichoblastic neoplasm. Dermatol Surg 2001;27:663-6.  Back to cited text no. 3
Headington JT. Tumors of the hair follicle. A review. Am J Pathol 1976;85:479-514.  Back to cited text no. 4
Kazakov DV, Vittay G, Michal M, Calonje E. High-grade trichoblastic carcinosarcoma. Am J Dermatopathol 2008;30:62-4.  Back to cited text no. 5
Cogrel O. Surgical management of localized trichoblastic carcinoma of the conchal bowl by means of a retroauricular revolving door island flap. Ann Dermatol Venereol 2014;141:474-5.  Back to cited text no. 6
Kazakov DV, Spagnolo DV, Kacerovska D, Rychly B, Michal M. Cutaneous type adnexal tumors outside the skin. Am J Dermatopathol. 2011; 33:303-15.  Back to cited text no. 7
Bordelon J, Choudhary S, Ho J, Pugliano-Mauro M. Differentiating basal cell carcinoma and trichoblastoma in a nevus sebaceous. J Am Acad Dermatol 2018;79:AB108.  Back to cited text no. 8
Thomas M, Bruant-Rodier C, Bodin F, Cribier B, Huther M, Dissaux C. Why is it important to differentiate trichoblastic carcinomas (CT) from basal cell carcinomas (CBC). About 21 cases. Ann Chir Plast Esthet 2017;62:212-8.  Back to cited text no. 9
Hua C, Velter C, Osio A, Lebbe C, Basset-Seguin N, Cribier B, et al. Locally aggressive trichoblastic tumours (Low-grade trichoblastic carcinomas): Clinicopathological analysis and follow-up. Acta Derm Venereol 2018;98:126-7.  Back to cited text no. 10
Morgan RF, Dellon A, Hoopes JE. Pilar tumors. Plast Reconstr Surg 1979;63:520-4.  Back to cited text no. 11
Batman PA, Evans HJ. Metastasising pilar tumour of scalp. J Clin Pathol 1986;39:757-60.  Back to cited text no. 12
Lee KH, Kim JE, Cho BK, Kim YC, Park CJ. Malignant transformation of multiple familial trichoepithelioma: Case report and literature review. Acta Derm Venereol 2008;88:43-6.  Back to cited text no. 13
Laffay L, Depaepe L, d'Hombres A, Balme B, Thomas L, De Bari B. Histological features and treatment approach of trichoblastic carcinomas: From a case report to a review of the literature. Tumori 2012;98:46e-9e.  Back to cited text no. 14
Harari PM, Shimm DS, Bangert JL, Cassady JR. The role of radiotherapy in the treatment of malignant sweat gland neoplasms. Cancer 1990;65:1737-40.  Back to cited text no. 15
Lepesant P, Crinquette M, Alkeraye S, Mirabel X, Dziwniel V, Cribier B, et al. Vismodegib induces significant clinical response in locally advanced trichoblastic carcinoma. Br J Dermatol 2015;173:1059-62.  Back to cited text no. 16
Battistella M, Mateus C, Lassau N, Chami L, Boukoucha M, Duvillard P, et al. Sunitinib efficacy in the treatment of metastatic skin adnexal carcinomas: Report of two patients with hidradenocarcinoma and trichoblastic carcinoma. J Eur Acad Dermatol Venereol 2010;24:199-203.  Back to cited text no. 17


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