Acantholytic Squamous Cell Carcinoma: a Diagnostic Pitfall on Cytology

Abstract

Acantholytic squamous cell carcinoma is an infrequent subtype of squamous cell carcinoma. This tumour variant being rare in itself has been rarely described at the penile location, thus leading to a limitation on information of pathological and immunohistochemical findings and prognosis. Clinical observations indicate an aggressive biologic behaviour. The cytological features on fine-needle aspiration cytology samples have rarely been described in literature. It is imperative for pathologists to be aware of the cytological features so as to allow the distinction of this variant from conventional squamous carcinoma. Here, we explore an intriguing case of a metastatic tumour to inguinal lymph node with the primary lesion at the penis which constituted a diagnostic challenge on cytological examination.

Keywords: Acantholytic squamous cell carcinoma; Cytology; Melanoma; Penis; Vimentin.

Fig. 1

Clinical image showing an ulceroproliferative growth arising from the glans of the penis and involving the preputial skin

Fig. 2

a,b Cytological smears showing high cellularity with presence of malignant cells predominantly singly dispersed and loose cohesive groups (low power view, PAP × 40, HE × 40); c,d high power view showing individual cells, ovoid to polygonal in shape, round to ovoid nuclei with moderate to abundant cytoplasm imparting a plasmacytoid morphology (HE × 400, PAP × 400)

Fig. 3

a Histopathological image showing a diffusely infiltrative tumour with extensive dyscohesion (HE × 400); b IHC: p63 positive (× 400); c IHC: CK5/6 positive (× 40); d IHC: vimentin positive (× 40)