|Year : 2021 | Volume
| Issue : 2 | Page : 197-199
Morphoeic basal cell carcinoma – an unusual tumor variant at an unusual site
C Chandrakala, GK Tharini
Department of Dermatology, Government Villupuram Medical College, Viluppuram, Tamil Nadu, India
|Date of Submission||15-Apr-2020|
|Date of Acceptance||02-Jul-2020|
|Date of Web Publication||26-Aug-2021|
Department of Dermatology, Government Villupuram Medical College Hospital, Mundiyambakkam, Villupuram - 605 601, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Basal cell carcinomas (BCC) are malignant neoplasm arising from the basal layer of epidermis, seen almost exclusively on hair-bearing areas of skin. There are many clinical and histopathological variants in BCC. The tumor commonly seen at the site of excessive sun exposure. It is a locally invasive tumor with rare metastasis. The most common site for the development of morphoeic BCC is over the face. Clinically, morphoeic BCC presents as morphea such as sclerotic plaque and histopathologically as densely hyalinized stroma with angulated strands of neoplastic basaloid cells. Ulceration of the lesion is uncommon in this type. We report a case of morphoeic BCC, an unusual tumor variant occurring over the back.
Keywords: Basal cell carcinoma, mixed type, morphoeic basal cell carcinomas
|How to cite this article:|
Chandrakala C, Tharini G K. Morphoeic basal cell carcinoma – an unusual tumor variant at an unusual site. Clin Dermatol Rev 2021;5:197-9
| Introduction|| |
Basal cell carcinoma (BCC) is a most common skin malignancy arising from the basal layer of epidermis. It usually develops in sun-exposed skin and is more common in head and neck region. BCC is a locally invasive tumor with rare metastasis. The morphoeic or sclerodermiform BCC is an uncommon tumor with dense fibrous tissue stroma produces a thickened plaque like lesion over the face rather than an elevated nodule.
| Case Report|| |
A 46-year-old female presented with a history of asymptomatic firm lesion in the upper back for 1 year and black discoloration and ulceration over the lesion for 6 months. There was no history of trauma or any other insult at the lesional site prior to the onset of lesion. The lesion ulcerated on its own after 6 months. She also denied application of any topical medication over the lesion. She was a farmer by occupation and had excessive sun exposure. There was no history of swelling in the neck or in the axilla.
On examination, there was a slightly depressed indurated plaque with shiny atrophic skin and some areas showing hyperpigmentation and ulceration over the plaque [Figure 1]. The margins of the indurated plaque were ill-defined and the lesion was merging with the surrounding normal skin. There was a mild tenderness over the lesion. The regional lymph nodes were not enlarged. Chest X-ray, ultrasound abdomen, and other blood investigations were normal. Serological test for HIV was nonreactive.
|Figure 1: Morphoeic basal cell carcinomas over the upper back showing shiny atrophic skin at the periphery with hyperkeratotic scaling and ulceration in the center|
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Skin biopsy showed atrophic epidermis and the dermis showed larger aggregates of tumor cell nests in the upper dermis and a dense fibrous stroma in the form of homogenized collagen involving the full thickness of dermis similar to morphea [Figure 2]. The basaloid tumor cell nests were sparse and showed peripheral palisading of lesional cell nuclei [Figure 3]a. There was retractional clefting between the stroma and the tumor masses in some areas [Figure 4]. Inflammatory infiltrate was more in the upper dermis and around the tumor masses. Melanin pigment was also seen in the dermis, more around the tumor masses. Tumor masses showing follicular differentiation [Figure 3]b and squamous cell formation was also seen in the histological section [Figure 4]. The deep dermis showed compact, homogenized, hypocellular collagen bundles, and sparse appendageal structures. Replacement of fatty tissue by homogenized dense collagen was seen in the subcutis [Figure 2]. Our patient was a case of morphoeic BCC diagnosed with the characteristic clinical and histological findings and was referred for wide surgical excision.
|Figure 2: Scanning view showing hyperkeratosis, atrophic epidermis, tumor cell nests, homogeneous thick collagen bundles in the dermis and replacement of subcutaneous fat with collagen bundles|
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|Figure 3: (a) Nodular tumor cell nest showing peripheral palisading (H and E, ×400). (b) Hyperkeratosis, atrophic epidermis, tumor cell proliferation from the basal layer, basal cell mass showing keratotic differentiation (black arrow) (H and E, ×100)|
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|Figure 4: Retraction clefting around the tumor masses with metatypical change (black arrow) (H and E, ×100)|
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| Discussion|| |
BCC is a malignant tumor arising from the nonkeratinizing cells of the basal layer of the epidermis.
The annual incidence of BCC is 2.75 million new cases worldwide. It is more common in elderly individuals, but is increasingly common in people younger than 50 years of age. BCC develops in children and adolescent age group, if they have certain genodermatoses. The predisposing factors for BCC are ultraviolet (UV) light exposure, light hair and eye color, mutations in regulatory genes, exposure to ionizing radiation, exposure to arsenic, and alterations in immune surveillance. BCC has also been reported to occur in old scars, chronic ulcers, sinuses and the sites of chronic inflammation as that of squamous cell carcinoma. The exposure to UVB spectrum of UV light induces mutations in tumor suppressor genes. Mutations in the PTCH1 gene of Hedgehog signaling pathway is also an important cause for tumor development.
Clinically, there are five types of BCC such as nodular, pigmented, superficial, morpheaform type, and fibroepithelioma of Pinkus. All types commonly occur over the face except superficial type, occurs on the trunk and fibroepithelioma of Pinkus, occurs usually on the lower back. The morphoeic type has been reported to occur almost exclusively over the face.
Morphoeic BCC manifests as a solitary, smooth, shiny, flat or slightly depressed, yellowish plaque with ill-defined margins as that of morphea, finally goes for ulceration and constitutes 5% of all BCC.
Histologically, nodular BCCs usually show solid tumor masses with peripheral palisading cells. Superficial BCCs shows buds and irregular proliferations of tumor tissue attached to the undersurface of epidermis. Pigmented BCCs show features similar to nodular BCC but with more number of melanocytes and melanin. In fibroepithelioma, long thin, branching, anastomosing strands of BCC are embedded in a fibrous stroma.
Morphea like or sclerosing type usually shows groups of tumor cells arranged in elongated strands and small islands of tumor cells embedded in a dense fibrous stroma. Most of the strands are narrow, often one cell thick. However, there are reports of larger aggregates of tumor cells and strands of tumor cells showing branching pattern in morpheaform type.
In our case, the histological section showed mixed pattern of BCC with solid tumor masses. The dermis showed compact, thickened, homogenized collagen bundles with sparse appendageal structures suggestive of morphoeic type and also showed features of keratotic BCC and metatypical BCC changes in some areas and pigment deposition was also seen within and around the tumor nodules. There were no horn cysts.
Morpheaform BCC has to be differentiated from desmoplastic trichoepithelioma (DTE). DTE presents as solitary, asymptomatic, firm to hard annular sclerotic lesion or papular lesion with a central dell or depression, commonly occur over the cheek of female patients. Histologically, DTE shows epidermal hyperplasia, horn cysts, narrow strands of basaloid cells, desmoplastic stroma, foreign body granulomas from broken cysts, areas of calcification or ossification and there are no clefts between nests of tumor cells and stroma.
Immunohistochemical staining helps to differentiate DTE from morpheaform BCC. DTE is positive for CK15 in tumor cells, CK34 in peritumoral stroma with the presence of CK20 positive Merkel cells within the lesion. Morpheaform BCC shows positivity for Periodic acid–Schiff stain and CEA androgen receptor.,
Treatment options available for BCCs include curettage and electrodessication, surgical excision, Mohs micrographic surgery, topical 5-flurouracil, topical imiquimod, cryotherapy, radiation therapy, photodynamic therapy, and intralesional alpha interferon. Mohs micrographic surgery is the preferred treatment modality for morpheaform BCC as it is prone for recurrences after surgical excision because of the poorly defined tumor margins. Our case is unique in its occurrence over the back as morphoeiform BCC commonly occurs on the face and histologically showing nodular tumor masses with absence of thin strands of tumor cells, presence of morphea-like collagen changes in the dermis and subcutis and the presence of keratotic and metatypical BCC features in the same histological section.
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 initial s 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.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]