Fibroepithelioma of Pinkus in continuity with nodular basal cell carcinoma: A rare presentation.

Fibroepithelioma of Pinkus and nodular basal cell carcinoma (BCC) are different morphological variants of BCC. It is very rare to see both the variants together in a single lesion. Here we report a case of a 56-year-old female who presented with a nodule on the trunk, which on biopsy showed features of both nodular BCC and fibroepithelioma of Pinkus.

INTRODUCTION

Basal cell carcinoma (BCC) is one of the common malignant cutaneous neoplasms seen in the elderly. There are various clinical and histopathological variants of BCC.[1] Nodular basal carcinoma is a more frequently seen variant, whereas fibroepithelioma of Pinkus is rare. Both the variants have distinct clinical and histopathological features. It is very rare to see both the variants together in a single lesion.

CASE REPORT

A 56-year-old female presented with an asymptomatic nodular lesion on the trunk. The mass was present since 3 years and had gradually increased in size. Clinical examination revealed a single nodule of size 3 cm × 4 cm on the lateral part of abdomen. The nodule showed hyperpigmented beaded border and pinkish center. It was dome-shaped in appearance and had surface telangiectasia [Figure 1]. Minimal scaling and crusting was seen on the surface of the nodule. There was no significant lymphadenopathy or hepatosplenomegaly.

Figure 1

Nodule with pigmented beaded border and central dome-shaped, pinkish area on the lateral part of abdomen

A biopsy from the nodule showed two different histological patterns, nodular at one half and anastomosing pattern at the other half [Figure 2]. Both the tumor patterns were connected with the surface epidermis and also with one another. Nodular masses were made up of basaloid cells with peripheral palisade, and cleft was noted between the tumor islands and the stroma [Figure 3]. Large aggregates of melanin pigment were seen in the nodular zone. These features were suggestive of nodular BCC. On the other half, cords and columns of basaloid cells were seen forming reticulated network. At places peripheral palisading, melanin pigment, and follicular germ-like structures protruding were seen [Figure 4]. These features were suggestive of fibroepithelioma of Pinkus. Thus the histopathological and clinical features were suggestive of nodular BCC in continuity with fibroepithelioma of Pinkus.

Figure 2

Masses of basaloid cells (left half) and cords and columns of basaloid cells forming reticulated pattern (right half), (H and E, ×100)

Figure 3

Aggregations of basaloid cells with palisading at the periphery, cleft formation, and melanin pigment deposition is also seen (H and E, ×200)

Figure 4

Cords and columns of basaloid cells with peripheral palisading. Follicular germ-like structures are seen protruding at places. The stroma is rich in fibrocytes. (H and E, ×200)

DISCUSSION

Nodular BCC is the commonest variant of BCC that presents as pearly or pigmented papule or nodule with rolled out border with or without ulceration on the sun-exposed parts. Nodular BCC histologically shows tumor masses made up of basaloid cells having peripheral palisading and cleft between the surrounding stroma and the tumor islands. Variable amount of melanin pigment and mucin deposition can also be seen.

Fibroepithelioma of Pinkus was first described in 1953.[2] It is considered as a rare variant of BCC with distinct clinical and histopathological features. It presents as skin-colored to pink sessile or pedunculated papule or nodule on the trunk often resembling a fibroma. It is commonly reported to occur in adult males aged 40–60 years. However, a few cases in pediatric population have been reported.[3] Fibroepithelioma shows different histopathological features as compared to nodular BCC. It consists of basaloid cells arranged in cords and columns, which anastomose with each other. Stroma surrounding these cords and columns is thick and rich with fibrocytes. These columns and cords may show palisading and follicular germ-like structures formation. Many of the cords and columns show connections with the surface epidermis.

Apart from cases of nodular BCC with fibroepithelioma of Pinkus, other histological variants of BCC-like adenoid-cystic BCC and keratotic BCC has been described with fibroepithelioma of Pinkus.[45]

The classification of fibroepithelioma of Pinkus as BCC or trichoblastoma remains controversial. Fibroepithelioma of Pinkus is considered as an unusual variant of BCC by some authors, whereas others consider it to be a benign analogue of BCC.[6]

Presence of fibroepithelioma of Pinkus in continuity with nodular BCC in this case supports its malignant nature. This case is being published for its rare presentation.

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Conflicts of interest

There are no conflicts of interest.