Dogliotti and Phillips classifications are unsuitable for grading the histopathological findings of exogenous ochronosis

Abstract

Background Cutaneous exogenous ochronosis (EO) is frequently graded and staged according to the Dogliotti or Phillips classification system, both in research studies and in clinical practice. There are no data to support the use of these systems in either of these settings. These systems additionally purport that the clinical and histopathological findings of EO are concordant; however, anecdotal evidence suggests otherwise. We aimed to determine the clinical‐histopathological concordance rates in EO and to assess the suitability of the Dogliotti and Phillips classification systems for the grading and staging of EO lesions. Methods Five cutaneous EO cases diagnosed at our institution were studied. Clinical and histopathological data were obtained by medical record and histopathology slide review. Each case was assigned a clinical and histopathological grade according to both the Dogliotti and Phillips classifications. Clinical‐histopathological concordance rates were determined for each classification. Results Clinical‐histopathological concordance was seen in 80% and 60% of EO lesions when graded according to the Dogliotti and Phillips classifications, respectively. Conclusions Cutaneous EO lesions do not consistently show clinical‐histopathological concordance. Although the Dogliotti and Phillips classifications may have clinical utility, they are not suitable to grade EO histopathologically.

Diagnostic tools for hyperpigmentation disorders in skin of color: An updated review

“…When ochronosis lesions were graded using the Dogliotti and Phillips classifications, clinical‐histopathological concordance was observed at 80% and 60% of cases, respectively. These findings suggest that although the Dogliotti and Phillips classifications may be helpful in clinical settings, they are not appropriate for histological grading of ochronosis 46 . At the microscopic level, ochronotic bodies are the hallmark feature of skin tissue affected by ochronosis.…”

“…The pigment depositions in ochronosis are characterized by blue‐gray dots and globules with a “caviar‐like” appearance 50 . Some specific patterns give hints to diagnosing ochronosis via dermoscopy and include the obliterated follicular openings and elongated or curvilinear “banana‐like” structures, often observed together with degenerated collagen fibers in the papillary dermis 28,36,46 . Since ochronosis already poses significant clinical challenges for clinicians and is emotionally distressing for patients, dermoscopy provides a noninvasive alternative to diagnose and assess proper management of this condition.…”

“…These findings suggest that although the Dogliotti and Phillips classifications may be helpful in clinical settings, they are not appropriate for histological grading of ochronosis. 46 At the microscopic level, ochronotic bodies are the hallmark feature of skin tissue affected by ochronosis. They are believed to develop from the elastotic fibers resulting from severe, prolonged solar elastosis.…”

Exogenous Ochronosis: Clinicopathological Correlation in Indian Patients and the Practical Applicability of the Dogliotti and Phillips Classification Systems

“…Earlier considered a complication of topical hydroquinone use only over the long term [2], some studies have pointed to a shorter period of hydroquinone usage leading up to a diagnosis of ochronosis. Second, from few and far between case reports, the number of EOs has been increasingly reported in recent days [3,4]. So far, the only classification systems with a clinicopathological correlation in use for grading EO are those proposed by Phillips and Dogliotti, despite some evidence of their lack of practical applicability [3].…”

“…Second, from few and far between case reports, the number of EOs has been increasingly reported in recent days [3,4]. So far, the only classification systems with a clinicopathological correlation in use for grading EO are those proposed by Phillips and Dogliotti, despite some evidence of their lack of practical applicability [3]. Three clinical stages are described for EO according to Dogliotti, the first is erythema and mild pigmentation; the second is hyperpigmentation, milia, and mild atrophy; and the third stage presents with papulonodular lesions [5].…”