Vol 9, No 4 (2023)
Case report
Published online: 2023-12-12

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Forum Dermatologicum

2023, Vol. 9, No. 4, 162–166

DOI: 10.5603/fd.97321

Copyright © 2023 Via Medica

ISSN 2451–1501, e-ISSN 2451–151X

Trichilemmal carcinoma of the groin area of unknown primary site

Krzysztof Kowalik1Katarzyna Hetman2Marta Suchomska1Michał Falco3Anna Gruszczyńska4Krystian Kasperowicz5Jerzy Grabarek6Andrzej Modrzejewski1
1Clinical Department of General Surgery, Pomeranian Medical University, Szczecin, Poland
2Department of Clinical Oncology, West Pomeranian Oncology Center, Szczecin, Poland
3Clinical Department of Radiotherapy, Pomeranian Medical University, West Pomeranian Oncology Center, Szczecin, Poland
4Department of Forensic Medicine, Pomeranian Medical University, Szczecin, Poland
5Faculty of Health and Life Sciences, Northumbria University in Newcastle upon Tyne, United Kingdom
6Pathomorphology Laboratory, 109 Military Hospital with Outpatient Clinic, Szczecin, Poland

Address for correspondence:

Krzysztof Kowalik, MD, Clinical Department of General Surgery,
Pomeranian Medical University, 9–11 Piotra Skargi Street,
70–965 Szczecin, Poland;
e-mail: krzysztof.kowalik.uro@gmail.com

Received: 7.09.2023 Accepted: 28.11.2023 Early publication date: 12.12.2023

The authors present a case of a 49-year-old patient with a trichilemmal carcinoma of an unknown primary site. The groin tumour gradually enlarged over 6 months to a diameter of about 6 cm and was treated as an inguinal hernia. Specimens were taken from the tumour for histopathological examination, which revealed squamous cell carcinoma. In the meantime, ulceration of the tumour with leakage of pus appeared. The patient was referred for a computed tomography (CT) scan. A computed tomography scan exposed enlarged lymph nodes in the groin on the side of the tumour. Surgical treatment was undertaken involving excision of the tumour and a lymphadenectomy along the iliac vessels. Carcinoma was detected from the hair sheath. Chemotherapy and radiotherapy were undertaken. After four months, there were no signs of local recurrence or distant metastasis. The authors discuss the diagnostic difficulties encountered and the various treatment options for trichilemmal carcinoma.
Keywords: trichilemmal carcinoma, metastases, lymph nodes, chemotherapy
Forum Derm. 2023; 9, 4: 162166


Trichilemmal carcinoma (TLC) is a rare malignant tumour that originates from the external root sheath of the hair. Sun exposure is considered a risk factor, as cited by other authors [1, 2]. The average age of TLC diagnosis is 70 years, with a predominance of male patients in the affected group [3, 4]. Typically, this tumour develops on hairy body parts, but it can also occur in non-UV-exposed areas in individuals with compromised immune systems [5, 6]. Other established risk factors for TLC include exposure to radiation, local injuries or burns, immunosuppression, as well as hereditary conditions such as xeroderma pigmentosum or Cowden’s disease [3]. The first case of TLC was documented by Headington in 1976 [7]. He identified that TLC is composed of atypical clear cells derived from skin appendage keratinocytes. The key histological feature distinguishing TLC from other skin tumours is the presence of trichilemmal keratinization. The tumour lacks a granular layer between the spinous and keratin layers [7]. For skin-afflicted cases, local, wide excision with tumour-free margins constitutes the primary treatment. There is also growing evidence of the effectiveness of Mohs micrographic surgery, involving precise removal of tumour tissue under the microscope to spare healthy tissue [2]. In cases of TLC with metastasis, several chemotherapy options are employed. Combining cisplatin with cyclophosphamide, 5-fluorouracil, vinblastine, and bleomycin slow the progression of metastatic disease [8–10]. Literature reports indicate that recurrences of TLC after successful treatment are rare [2].


A 49-year-old female patient presented to a cardiologist due to severe abdominal pain and chest discomfort (attributed to a previous COVID-19 infection). A year and a half earlier, the patient noticed a palpable lump in the right inguinal area, which initially did not cause any pain. However, the patient observed that the inguinal lump was gradually enlarging. The patient visited her general practitioner, who recommended an ultrasound examination. On examination, bilateral inguinal hernias containing omentum majus was diagnosed. The patient was referred by her primary care physician for right-sided inguinal hernia repair. The surgeon, after examining the patient, clinically ruled out the presence of an inguinal hernia and requested an abdominal cavity CT scan. The abdominal CT scan revealed an irregular, strongly enhancing after-contrast administration structure measuring approximately 60 mm × 50 mm with a hypodense centre in the right inguinal area (Fig. 1). The radiologist suspected a tumour with signs of necrosis or a lymph node with signs of degeneration. Adjacent to the aforementioned lesion, two pathological lymph nodes measuring 26 mm × 21 mm and 21 mm × 21 mm were seen. Additionally, several lymph nodes up to 15 mm in size were identified around the external iliac vessels and paraaortic vessels (below the bifurcation). Enlarged lymph nodes up to 9 mm were also noted, raising concerns of tumour metastases. The CT scan also revealed an enlarged uterus with significant contrast enhancement.

Figure 1. Computed tomography (CT) scan image of a lymph node lesion in the right inguinal region

The patient was referred to the surgery clinic, where a biopsy of the inguinal region lesion was performed, and the collected specimen was sent for histopathological analysis. Histopathological analysis of the biopsy sample revealed infiltrating, moderately differentiated squamous cell carcinoma (G2) with areas of necrosis. Considering the suspicion of primary cervical cancer in the patient, a gynae­cological consultation was requested. A gynaecological examination revealed an irregular, enlarged cervix and uterus. A gynaecological ultrasound examination described an enlarged, heterogeneously echogenic cavity of the uterus. The cytological examination did not reveal signs of malignancy. A PET scan was performed to identify the primary site of squamous cell carcinoma in the right inguinal lymph nodes. The PET scan identified a 17 mm diameter area of increased metabolism in the right adnexa. Metabolically active lymph nodes in the right inguinal region, suggestive of metastatic changes, as well as common iliac lymph node measuring up to 21 mm were also identified.

A chest CT scan of the patient did not reveal any suspicious oncological changes. Corynebacterium amycolatum was cultured from the ulceration of the inguinal tumour (but as the strain is considered to be non-toxigenic, antibiotic therapy was not recommended).

During the diagnostic process, the primary site of the tumour could not be identified. Malignancy in the genital organs was ruled out. The patient underwent surgery at the surgery clinic, where resection of the right inguinal tumour with pelvic lymph node dissection was performed.

Figure 2. Image after surgery of right inguinal tumour resection with pelvic lymph node dissection

The tumour was excised from a cut in the thigh, along and below the inguinal ligament. Upon dissecting the skin over the 8 cm × 4 cm-sized tumour, a necrotic and suppura­ting mass was observed. Additionally, significantly enlarged lymph nodes measuring up to 4 cm were removed from the area of the external iliac artery, common iliac artery, and aortic bifurcation by extraperitoneal incision (Fig. 2). The histopathological postoperative material (sectioned tumour and lymph nodes) revealed metastasis of trichilemmal carcinoma cells (Fig. 3, 4). The intraoperative view of the right inguinal tumour is presented in Figure 5.

Figure 3. Visible tumour infiltration corresponding to trichilemmal carcinoma. The infiltration originates from the right inguinal tumour. Focal necrotic areas are visible in the central part
Figure 4. Section of a metastatically altered lymph node. Visible tumour infiltrations corresponding to trichilemmal carcinoma. Focal necrotic areas of the tumour are also visible in the specimen

In the further stage of treatment at the Oncology Department, the patient received 6 courses of chemo­therapy with cisplatin at a dose of 80 mg/m2 in combination with radiotherapy (RT). The radiotherapy plan was deve­loped using a 3D planning system based on the performed treatment planning with a CT scan. The radiation was delivered in 25 fractions using the volumetric modulated arc therapy (VMAT) technique on a Halcyon accelerator (Varian, a Siemens Healthineers company). A dose of 45 Gy was given to the external and internal iliac lymph nodes on the left side, while a dose of 50 Gy was given to the inguinal, external and internal iliac lymph nodes on the right side, common iliac lymph nodes, and the tumour bed (tumour bed this is what is left after the cancer has been removed surgically). During treatment, grade 1 skin erythema according to RTOG and grade 2 early gastrointestinal reactions according to RTOG (loose stools) were observed. After 6 sessions of radiochemotherapy, a follow-up computed tomography scan did not reveal local recurrence or distant metastases as of the time of publication. The patient remains under further oncological observation.

Figure 5. Inguinal tumour excised during the procedure a bundle of enlarged lymph nodes; intraoperative image


Trichilemmal carcinoma (TLC) is a rare malignant tumour arising from the outer sheath of the hair follicle and is primarily derived from the external root sheath of the hair follicle [1, 2]. It was first described by Headington [7] and is most commonly found on the face and neck of older individuals [3, 4]. Trichilemmal carcinoma is rarely documented in patients under 40 years of age, though Reis and colleagues [6] reported a case of TLC in a 9-year-old boy with xeroderma pigmentosum, followed by another case of a 25-year-old patient [11]. Clinically, TLC often presents as an asymptomatic polypoid or exophytic mass. The tumour may occasionally show ulcerations, irregular borders, or “flakes” resembling basal cell carcinoma (BCC), squamous cell carcinoma (SCC), keratoacanthoma, or proliferating trichilemmal cysts [1, 6]. While TLC can exhibit local malignancy, it often has a benign nature. when treated with radical tumour resection [1, 6, 12]. In the case described by the authors, the tumour was initially misdiagnosed as an inguinal hernia. The patient sought medical attention due to the increasing size of the right inguinal mass for six months, without experiencing pain. Based on the ultrasound examination, the patient was referred for hernioplasty, but the surgeon during the physical examination ruled out the presence of an inguinal hernia. An abdominal and pelvic CT scan with contrast revealed a large enhancing metastatic tumour in the right inguinal area. Subsequent biopsy of the inguinal lymph node confirmed squamous cell carcinoma G2. The patient underwent radical tumour resection, and histopathological examination confirmed the final diagnosis of trichilemmal carcinoma. The present case highlights that TLC can also occur in the abdominal region. In a literature review conducted by other authors, only one case of abdominal TLC has been described thus far [13]. The authors recommend differentiating a suspicious mass in the groin from a neoplastic lesion.

The primary treatment for TLC is radical surgical tumour resection. In the cited literature review, 35 cases were surgically treated, with recurrence occurring in only two patients one of whom experienced three recurrences. These patients were observed for periods ranging from 2 months to 10 years [13, 14], indicating that radical tumour resection delivers excellent treatment outcomes. Increasingly, cases of radical surgical resection of TLC using the Mohs method are being reported [5, 15–17]. This approach has also shown satisfying treatment outcomes without recurrence. Patients treated with the Mohs method were often observed for up to 20 months without recurrence [5, 15–17]. In the case of metastatic lesions, as seen in the described patient with a resected right inguinal tumour and documented lymph node metastasis, systemic chemotherapy should be considered.

In the literature, there is no specific treatment protocol described for systemic therapy in trichilemmal carcinoma (TLC) with metastases due to the limited number of cases. It is recommended to use treatment approaches similar to those used for skin cancers [3]. There are cases of TLC with metastasis after radical resection of the primary tumour, they were described and treated with cisplatin and cyclin [8, 13]. There is also data suggesting that cisplatin in combi­nation with cyclophosphamide, 5-fluorouracil, vindesine, and bleomycin can slow down the progression of metastasis [8–10]. A case report published in 2010 described a patient aged 63 who received four sessions of combined chemotherapy (cisplatin 56 mg/m2 with cyclophosphamide 400 mg/m2). Partial remission with confirmed reduction of abdominal lymph nodes was achieved. This chemotherapy regimen was found to inhibit tumour growth but did not lead to remission. No serious complications were noted during treatment, but chemotherapy was discontinued as the patient requested [8]. It is suspected that the CAV regimen (cisplatin, adriamycin, vindesine) used for advanced basal cell carcinoma may be effective in TLC with metastases [18, 19]. In another reported case in 2001, cisplatin 75 mg/m2 was administered on the first day along with etoposide 100 mg/m2 for three days. Partial remission was achieved, and no disease progression was observed for six months [20]. Weiss et al. found a good response to cisplatin and 5-fluorouracil [21]. However, Roismann et al. [10] indicated that using four cycles of chemotherapy with 5-fluorouracil and cisplatin was associated with a poorer prognosis in the case they presented. This patient, a 35-year-old male diagnosed with basal cell carcinoma, later developed TLC in the same location. After surgery for BCC, the patient received postoperative radiotherapy with a total dose of 6000 cGy. Five years later, disease recurrence occurred, and after resection, the patient received 1000 mg/m2 of 5-fluorouracil along with 75 mg/m2 of cisplatin. Disease progression was observed four months after chemotherapy. Adjuvant radiotherapy was then administered with a total dose of 4320 cGy [10]. The literature includes a case of a 69-year-old woman who underwent postoperative radiotherapy. During a follow-up visit two years after completing radiotherapy, no disease recurrence or metastases were observed. Another case involved a 53-year-old woman who did not receive radiotherapy after tumour resection, as the multidisciplinary committee concluded that it would not provide significant benefit. No disease recurrence was observed during the two-year follow-up [22]. In this case the patient after radical resection, cisplatin was administered at a dose of 80 mg/m2 in cycles every 7 days in combination with radiotherapy, achie­ving a good treatment response. Due to the lack of clear treatment protocols in the literature, further study is required.


Patients with suspected groin lesions should consider the possibility of malignant changes, not only inguinal hernias. Radical tumour excision with enlarged lymph nodes followed by postoperative radiotherapy and chemotherapy appears to be a promising approach for advanced TLC.

Article information and declarations



Author contributions

KK, AG, KH, MF, AM preparation of the primary version of the manuscript; JG, MS, AM preparation of photographic documentation; KK preparation of the English-language version of the manuscript and language proofreading; KK, AG, KH literature review.

Conflict of interest

The authors declare no conflict of interest.

Ethics statement

No ethical issues.



Supplementary material



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