| Abstract|| |
Introduction: Basal cell carcinoma is the most common cutaneous malignancy which is exclusively observed on sun exposed and hair bearing areas of the face. Diagnosis: We report two rare cases of basal cell carcinoma, which presented as a diagnostic challenge because of rare histopathology. Findings: Both cases showed pigmentation, while one case resembled adenoid cystic carcinoma because of the glandular and ductal pattern of basaloid cells. Result: We present these cases because of rare histopathologic presentation.
Keywords: Adenoid type, basal cell carcinoma, histopathology, pigmented
|How to cite this article:|
Sharma P, Wadhwan V, Bansal V. Basal cell carcinoma: Histopathological gamut. Indian J Dent Res 2021;32:407-10
| Introduction|| |
Basal cell carcinoma (BCC), which constitutes 65% of the epithelial tumors, is the most common cutaneous malignancy, arising from basally located cells of epidermis and pilo-sebaceous unit. It is usually prevalent in adults, with its peak incidence in the sixth decade with male predilection. They are seen in children in association with genetic disorders like basal cell nevus syndrome, Bazex syndrome, Xeroderma pigmentosum, etc. It is exclusively observed on sun exposed and hair bearing areas of the face. Long exposure to sunlight predisposes to this malignancy especially in light-colored skin individuals, especially as a part of professional exposure such as in sports persons. Other predisposing factors include arsenic exposure, radiotherapy, and following burns and other scarring. However, about one-third of BCCs are also observed in the sun protected areas, and rarely intraorally, suggesting other factors such as genetic susceptibility may also be causative factor in BCC. Clinically, it is commonly seen in the form of a noduloulcerative growth in the head–neck region, especially on nose, eyelids, at the inner canthus of eyes, and behind the ears. Many histological subtypes occur, including solid, micronodular, infiltrative, and pigmented. Occasionally, we may come across rare histologic variants as the adenoid types, which can morphologically present as pigmented and nonpigmented nodule or ulcer without any site predilection. Two rare cases of pigmented nodular BCC, one showing adenoid histopathologic pattern with histological resemblance to adenoid cystic carcinoma, are presented here.
| Case Report|| |
A 55-year-old male patient presented with a large grayish ulceroproliferative growth seen on the right side of the face. Apparently, it was asymptomatic and persistently growing over a period of 6 years. On clinical examination, the lesion was a hyperpigmented ulcerated nodule measuring 5×3×3 cm and revealing black colored base and everted black margins involving the medial canthus, infraorbital area, and malar prominence [Figure 1]. Surrounding skin of the ulcer was blackish at areas and non-tender on palpation. While the floor of the ulcer provoked bleeding on touch at areas, the base was soft in consistency. General physical examination and systemic examinations were normal. There was no regional lymphadenopathy. Clinically, the provisional diagnosis was malignant ulcer, BCC, malignant melanoma, and squamous cell carcinoma. Incisional biopsy of the lesion revealed sheets and intertwining strands of basaloid cells forming duct and glandlike pattern giving an adenoid-basal appearance with entrapment of fibro-cellular stroma at areas [Figure 2]a. The islands of basaloid cells showed palisading at the periphery. Occasional mitotic figures were also observed. All surgical margins were free of tumor. Moderate amount of melanin pigmentation was prominently observed within islands and sheets of basaloid epithelial cells, along with melanin pigment in the melanophages present in the stroma surrounding tumor cells [Figure 2]b. A final diagnosis of pigmented adenoid BCC was rendered. The patient is fine 6 months after the surgical excision with no recurrence.
|Figure 1: Large rhomboidal ulcerated nodule with everted black margins seen on the right side of the face|
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|Figure 2: (a) Histopathology shows duct-like and glandular pattern of basaloid cells throughout the section (×40). (b) Hematoxylin and eosin-stained section shows moderate melanin pigmentation within the islands of basaloid cells (×100)|
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A 70-year-old female patient complained of a persistently enlarging necrotic growth on the right side of the face just below the medial epicanthus at the root of the nose since 15 years. The necrotic growth was initially smaller in size and has grown slowly to reach the present size. There was no history of trauma or any surgery in the past. There was no associated pain, paresthesia, or discharge from the lesion. It was a well-defined, rhomboidal-shaped solitary nodular lesion, measuring approximately 3×2×2 cm in size, with an area of ulceration on the superior aspect and showing rolled edges and fibrosed margins [Figure 3]. Physical examination was normal with no regional lymphadenopathy. Provisional diagnosis was pigmented BCC, nodular melanoma, dermatofibroma, and trichoepithelioma. Excisional biopsy of the lesion revealed ulcerated epithelium with numerous dysplastic basaloid epithelial cells arranged as large islands and sheets extending till the entire depth of the lesion [Figure 4]a. The islands displayed pleomorphism, hyperchromatism, palisading of peripheral cells, and areas of retraction between epithelial islands and adjacent stroma. The areas of melanin pigmentation were evident in the epithelial islands and stroma, along with moderate lymphoplasmacytic infiltrate [Figure 4]b. The final diagnosis was pigmented nodular BCC with tumor-free margins.
|Figure 3: Pigmented nodule seen on the right side of the middle third of face|
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|Figure 4: (a): Hematoxylin and eosin-stained section shows numerous dysplastic basaloid epithelial cells arranged as large islands (×40). (b) Areas of melanin pigmentation evident within the epithelial islands (hematoxylin and eosin stain; ×100)|
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| Discussion|| |
BCCs, also known as “ulcus rodens” by Jacob in 1827, manifests clinically as papulonodular lesion with a shiny transparent rim, with various degrees of induration, erythematous foci with telangiectasia or as cystic nodules, and sometimes as pigmented nodules. Nodular lesions appear to be a diagnostic challenge to even the most experienced physicians with nodular pigmented BCC as one of the most hard-to-diagnose lesions. Invasive nodular melanoma is the main differential diagnosis of pigmented BCC, which is attributed to its relative rapid growth with bleeding. Radiographically, magnetic resonance imaging assesses the perineural invasion and bony involvement in facial BCCs, while CT is used to evaluate the metastatic disease, the incidence of which is very low. Ultrasound plays a crucial role in differentiating BCC from other skin cancers as it shows hypoechoic or heterogeneous lesions with irregular borders and may exhibit characteristic hyperechoic spots. Clinically, pigmented BCC appears as a sharply demarcated nodule with a long-standing history of growth and usually showing ulceration. On the contrary, nodular melanoma generally starts as an expanding papule that increases in size quite rapidly. According to the degree of pigmentation, BCC lesions may look like seborrheic keratosis or even malignant melanoma. Both the presented cases were pigmented and also resembled malignant melanoma.
Histopathologically, BCC is an epithelial malignant tumor with a low malignant potential, consisting of masses of basaloid cells with a pale cytoplasm surrounding round hyperchromatic nuclei with a rough granulated chromatin pattern. Commonly, the islands are lined by characteristic palisading basaloid cells, whereas internally the arrangement of the cells is irregular. Multiple mitoses may be observed in many cases; however, mitoses may be rare in some lesions. Various histopathological types of BCC have been described; the highest number, 26, was described by Wade and Ackerman in 1978. Two basic criteria are considered in the classification, the histological growth pattern and histological differentiation. The histological growth pattern is more significant for it is decisive for categorizing the lesion into low-risk and high-risk type of BCC. High-risk type is more likely to show subclinical spread with a more frequent occurrence of local recurrences. The infiltrative and superficial types represent the high-risk type; the low-risk type includes the nodular variety that further shows histological variants like cystic and pigmented types of BCC. The adenoid type is one of the infrequently occurring variants of BCCs that has no site predilection, for example, can occur on back, axillae, and legs. Some authors, though, have reported eyelids as preferential site for adenoid BCC. Cases of adenoid BCC have been described in the literature on unexposed areas of skin and also at rare locations like cervix, prostate, and lumbosacral area., Recurrences of BCC are not an unusual occurrence and are generally due to inadequate excision of histopathologically tumor-free margins. Nevertheless, less than 400 cases have been reported where BCC has metastasized, metastatic rate ranging from 0.0028 to 0.55%. Adenoid BCC is regarded as a low-grade malignancy compared to other more common subtypes like nodular and morpheaform forms and treatment is similar to other BCCs.
Pigmented BCC only contains functional melanocytes producing melanin; an admixture of a certain dominant growth type and their presence as well as the presence of melanophages in the dermis have no influence on the biological behavior of the tumor. Both the cases presented here displayed pigmentation. Coexistence of two different histopathological types of BCC in the same anatomical site is an unusual observation. Different authors have documented the coexistence of BCC with mixed histology, showing a time gap between the adenoid and the nodular histologic types.
The cases presented here with ulcerated nodules with everted rolled margin. Histopathology of the first case displayed the adenoid type of pattern with lots of pigmentation. However, still, it needed to be differentiated from adenoid cystic carcinoma, which it mimicked histopathologically.
Adenoid cystic carcinoma is commonly seen in organs like salivary glands, breast, cervix, larynx, ceruminous, and lacrimal glands. If the metastases from adenoid cystic carcinoma of other organs is ruled out, then primary cutaneous adenoid cystic carcinoma (PCACC) is the most probable diagnosis. An extremely rare tumor, it usually occurs on the scalp, chest, and abdomen, arising as a firm large nodule measuring approximately 0.5–-8 cm with a persistent slow growth averaging 9.8 years prior diagnosis. Microscopically, PCACC is characterized by islands and cords of basaloid cells within glandular, cystic, cribriform, and tubular patterns; neural invasion is generally seen. Hyaline membrane-like or mucus-like material is evident in the glandular spaces. The absence of nuclear palisading and lack of connection with epidermis and retraction space help to differentiate it from BCC. It shows positivity with immunohistochemical markers like embryonic membrane antigen (EMA) and carcinoembryonic antigen. Rao AG reported negativity for antibodies to S100, EMA, and CK7 in adenoid BCC.
The prognosis of BCC is good, since the lesion grows slowly and does not tend to metastasize. Generally, it responds well to treatment modalities like curettage, electrodissecation, photodynamic therapy, topical imiquimod, cryotherapy, radiation therapy, and standard surgical excision. The recurrence of BCC depends on tumor treatment, biologic behavior of cancer, and immune status of the patient.
| Conclusion|| |
Both the cases showed pigmented nodular microscopic pattern; however, the first case displayed the coexistence of one of the rarest forms of BCC, i.e., adenoid type and nodular patterns histopathologically. Since the treatment and prognosis of BCC and adenoid cystic carcinoma varies, it was of critical importance to distinguish the adenoid BCC from adenoid cystic carcinoma which it mimicked remarkably. Both the neoplasms were pigmented, which does not affect the aggressiveness of the tumor, and the management of the adenoid and pigmented type does not vary from other types of BCC. Very few cases of adenoid and pigmented BCC have been reported in the literature.
BCC revealing two different histopathological patterns at the same site is an unusual occurrence. Adenoid type of histopathologic pattern in BCC is extremely rare and must be carefully distinguished from adenoid cystic carcinoma, which is a far more aggressive lesion.
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
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Dr. Preeti Sharma
BH-15, Pallavpuram, Phase-1, Meerut - 250 110, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4]