title: Pseudocarcinomatous Hyperplasia Hiding Lymphomatoid Papulosis: A "Low-Power View" Pitfall.
abstract: Pseudocarcinomatous hyperplasia (PCH) is a reactive proliferation of the epidermis that can be associated with many inflammatory and neoplastic conditions. Histologically, it is characterized by irregular strands of epidermis, usually at the level of the follicular infundibulum, projecting downward into the dermis. The differentiation between a well-differentiated squamous cell carcinoma and PCH can be particularly challenging when the biopsy is superficial and the causing lesion is dermal-based. Lymphomatoid papulosis (LyP) is an uncommon, self-healing, recurrent, cutaneous T-cell lymphoma, included among the primary cutaneous CD30-positive T-cell lymphoproliferative disorders. LyP is characterized by a chronic course of years to decades that does not compromise survival, even if patients with LyP are at risk for second cutaneous or nodal lymphoid malignancies. LyP and other lymphomas are major neoplastic causes of PCH and can be misdiagnosed or completely overlooked if the PCH is particularly exuberant. We describe the case of an otherwise healthy 55-year-old man who presented with a 3-month history of erythematous papules on upper and lower limbs. A diagnosis of LyP associated with PCH was made after 3 skin biopsies. The propensity of the CD30+ cutaneous lymphoproliferative disorders to an incognito growth pattern is well recognized, and a low-magnification scanning of the histological slides can be an inappropriate approach.
authors.affiliation: Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Bellafiore
authors.affiliation: Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Grenzi
authors.affiliation: Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Simonetti
authors.affiliation: Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy Simonetta.piana@asmn.re.it.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Piana
mesh_terms: D006801:Humans; D006965:Hyperplasia / Q000209:etiology / Q000473:pathology; D017731:Lymphomatoid Papulosis / Q000150:complications* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000473:pathology; D012871:Skin Diseases / Q000209:etiology* / Q000473:pathology; D012878:Skin Neoplasms / Q000150:complications* / Q000473:pathology
keywords: CD30 positive; lymphomatoid papulosis; pitfall; pseudocarcinomatous hyperplasia